


M^' 



^C(t^ 






HANDBOOK. ON 
DIE CASTINGS 

fPRECISION j 

I 



Gmii^ complete 
miormation about 
dies and casKn^ 
processes, metak 
methods of jfabri^^ 
at/on, fihishiW 
etc -with useful 
tahles. 



Q"' 



\i-^-ij^uii.\h\ 



Index Pages 94-95 



Copyright, 1919 



PRECISION CASTINGS COMPANY 
Syracuse, N. Y. 




u 



HAND-BOOK 



ON 



DIE-CASTINGS 



CONTAINING 



USEFUL INFORMATION FOR 

MANUFACTURERS AND 

ENGINEERS 



CONCERNING 



METALS, DESIGN, PROCESSES, 

METHODS OF FINISHING, 

FABRICATING, ETC., 

WITH TABLES 



By 
EDGAR N. DOLLIN 



Published by 

PRECISION CASTINGS CO., INC. 

SYRACUSE, N. Y. 

FACTORIES: 
FAYETTEVILLE. N. Y. and PONTIAC. MICH. 



^^1\"fc'\ 



Roaring forge and reddening glozv. 
Rhythmic siving of ha?nnier bloiv. 
May thy heartbeats never more 
Pulsate to the songs of war. 

Glorious deeds of mighty meyi 
Turn your strength to peace again. 
Muscle and braivn and gallantry now 
Turn to the factory , turn to the ploiv. 

From sea to sea, throughout the land. 
From northmost lakes to the Rio Grande, 
Assemble your hosts and gather your might 
Just as you did when you fought for your right. 

Up and to work! Lead the crusade. 
Masters of markets, princes of trade ; 
Carry Old Glory to the ports of the World — 
Fairly and justly and pro\}dly unfurled. 



FEB-.8 19!9©"-^'^'«* 



■J I 



Introduction 

The publication of this book is prompted by a desire to give users of die- 
castings and those interested in the art, complete information on the subject of 
die-castings and relative topics, as there is little available literature on the subject. 

We hope that the information herein given will bring about better co-opera- 
tion and understanding between users and producers, and will enable users to take 
greater advantage of the many economies and improvements in product and pro- 
duction made possible by the die-casting process. 

The present development and wide use of die-castings is not to be credited 
to any one man or organization. It is the result of contributions to the art made 
by many men and many organizations almost all of w^hom, it may be noted, did 
their work in the United States. Die-casting is today essentially an American 
industry. 

Die-casting machines for making type, which were the forerunners of the 
modern die-casting machines, were built in this country over seventy years ago. 
The modern industry is about thirty years old and came with the advent of quan- 
tity production of mechanical devices and machines. 

The Precision Castings Co., Inc., whose work is herein described, was organ- 
ized in 1916 to take over the E. B. VanWagner Mfg. Co., organized in 1907, and 
the Precision Die Castings Co., organized in 1910. These companies have for 
years been widely and favorably known for the high charactei of their product and 
service. The combination has produced an organization doing an unusually wide 
range of work in large volume without departing in any respect from the highest 
and most exacting standards. 

During the war our entire facilities have been devoted to government work, 
with few exceptions. We have made over one hundred different parts for motors, 




Precision Castings Co., Pontiac Plant. 




Jl'ater pump 

impeller, 
aluminum. 



Combustion 

motor zvater pump, 
zinc alloy. 



If'ater pump 

impeller, 
tin alloy. 



bombs, shells, grenades, aeroplanes, trench mortars, guns, etc., in large quantities. 
Of one part for hand grenades alone, we delivered over 25,000,000 in less than 
ten months. 

To be a die-casting, the part must be cast from fluid metal forced imder pres- 
sure other than gravity into a metallic mold, sufficiently below the temperature of 
the fluid metal to chill it. Parts poured in non-metallic molds, or poured in me- 
tallic dies by gravity only, or formed up in dies under pressure from a plastic or 
semi-fluid state, are not properly referred to as die-castings and lack the accuracy 
and range of design made possible by the die-casting process. So far, the only 
metals successfully die-cast on a commercial scale are the alloys of zinc, tin, lead 
and aluminum fusing below about 1300° F. Brass and bronze die-castings have 
been offered to the trade at various times by several concerns, some of which have 
discontinued business because they were unable to apply their process to general 
commercial requirements, and others have been able to produce only a few simple 
parts in limited quantities. It is not so difficult to die-cast a few samples, but 
production on a commercial scale is a different matter. The reasons for this will 
become apparent in the following pages. 

The inherent limitations of the die-casting process in its present development 
are such that only certain adaptable metals may be used, and when the particular 
strength and qualities of steels and bronzes are required, die-castings cannot be 
substituted for parts made of those metals. 

1 he process is more accurate than punching or drawing sheet metals, because 
there is not the same w^ear on the dies, nor is the spring and distortion of drawn 
metal a factor. Forgings or parts pressed from plastic metal are not as accurate 
as die-castings, and cannot be produced in as wide a range of design. 

The following list, showing some of the parts and devices for which die- 
castings are used, will give an idea of the extent to which the process has been 
applied in modern production. 



Adding Machines 

Automatic Controlling Devices 

Automobile Accessories and Parts 

Armature Parts 

Ammeter Housings and Plates 

Automatic Devices (small) 

Ammunition 

Air Pumps 

Atomizers 

Aeroplane Parts 

Bearings (plain) 

Brush Holders for Electric Motors 

Brackets of various kinds 

Cameras 

Cash Registers 

Carburetors 

Cigarette Machines 

Clocks 

Check Protectors 

Counting Machines 

Cup Dispensers 

Dental Appliances 

Door Checks 

Disinfecting and Sanitary Devices 

Electric Horns and Signals 

Envelope Machines 

Engine Governors 

Fire Extinguishers 

Fare Boxes and Registers 

Gears (small) 

Gas Engines 

Hinges 

Hardware 

Instruments of various kinds 

Knobs and Handles 

Lamps of various kinds 

Loose Leaf Book Binding Parts 

Magnetos 

Moving Picture Machines 

Motor Housings (small electric) 

Marking Machines 



Motorcycles 

Meters of all kinds 

Military Equipment and Devices 

Milking Machine Parts 

Numbering Machines 

Novelties 

Office Appliances 

Organs 

Optical Appliances 

Pencil Sharpeners 

Phonographs 

Pianos 

Piano Players 

Prepayment Devices 

Printing Presses and Machines 

Pulleys 

Plumbing Fixtures and Supplies 

Rubber Molds 

Switches (electric) 

Switch Keys 

Safety Razors 

Starting-, Lighting and Ignition Systems 

for Combustion Motors 
Sealing Machines 
Speedometers 
Stamp AfHxers 
Storage Batteries 
Soap Dispensers 

Soda Fountain Fittings, Pumps, Etc. 
Telephone Apparatus 
Time Clocks 
Typewriters 
Tabulating Machines 
Table and Kitchen Ware 
Thermostatic Devices 
Tractor Accessories and Parts 
Vacuum Cleaners 
Vending Machines 
Vibrators and Massage Devices 
Weighing Scales 
\^'^ater and Oil Pumps 



Speedometer frame — ttn alloy. 
Dimensions held to .001". Note 
hon.v the design reduces assem- 
bling! to a minimum. 





Vending madiine, 
zinc alloy. 



10 



I. Advantages of Using Die-Castings 

There are numerous advantages in the use of die-castings, many of which are 
not full}' appreciated until the castings are used for a given period and comparative 
data is available. In manj' cases they present manufacturing advantages peculiar 
to the job in hand, which it is not possible to point out in a general summary. 
Much depends on the character of the workmanship, ?naterial and service fur- 
nished. 

Die-castings which do not measure up to high commercial standards in these 
three particulars frequently cause troubles and delays which destroy the \tvy 
advantages which the process so admirably has over most others. It cannot be too 
strongly emphasized that comparative prices of die-castings offered from compet- 
ing sources should not be decisive in the placing of orders, although it by no means 
follows that the lowest bidder offers the poorest material. On the contrarv it 
frequently happens that the best die-castings are furnished by the lowest bidder 
because of his greater skill and experience which enable him to employ methods 
lower in cost and yet more thorough and effective in their results. 

Accuracy and ^^^ degree and range of accuracy which may 

_ ,^, L'T ^^ ^^^<^ is covered fully in a separate chapter 

Inter-Changeablllty u„der that heading (p. 51). it may be said 

here, that the elimination of error by avoiding 
the "human variable" is accomplished in die-castings to a greater extent than by 
any other process. The die is virtually a gauge and the size of the castings is in 
no way dependent upon the will or discretion of the operator. Consequently die- 
castings are interchangeable, which offers well understood advantages in manufac- 
ture and assembly and in making replacements for broken or worn parts. 

Finish and Appearance ^ die-casting, unlike a sand casting, h^s a 

perfect finish over its entire surface, which 
is smooth and clean-cut. The excellence of the finish is largely dependent upon 
the process used in manufacture, and upon the care and attention given the work. 
The highly developed and improved machines used by us make possible a standard 
which has never been attained by other methods. 

Die-castings have a solid, substantial appearance, which makes them more 
suitable for high class machines and devices than sheet metal parts, which have, 
in many cases, a cheap or "tin can" appearance. 

Almost any shape may be cast, frequently permitting a certain beauty or 
grace in outline which would be impractical or prohibitive in cost by other manu- 
facturing methods. 

RanP'e of DesiP'n ^ wider range of design is brought within practical 

and commercial limits by the die-casting process, than 
by any other single means. Many devices are now designed so that they may be 
made of die-castings, in whole or in part, and could not be commercially produced 
11 



b}^ an}- other method. A great many devices which could not be produced before 
the advent of die-castings, have been resurrected and marketed by means of the 
process. 

It is not possible to convey by any general statements the range of shapes and 
designs which may be die-cast, as the range of possible design is almost without 
limit. Each case, if it presents any difficulty, must be passed on by an experienced 
die-casting engineer to determine whether or not the design is practical. If the 
question is answered in the negative our engineers, when possible, always suggest 
changes which, if usable, will overcome the difficulties presented. 

With exceptions, the practical limit in weight is about 10 pounds in the zinc 
and tin alloys, about 15 pounds in the lead alloys, and about 3 pounds in alumi- 
num allovs. The size seldom exceeds 24" over all. 



Reduction of Assembling it frequently happens that two or more 

parts which must be produced sepa- 
rately and assembled by other processes, may be combined in a single die-casting. 
The result is greater accuracy, lower cost, better appearance, and generally greater 
rigidity and strength, with no opportimity for the separate parts to get out of line 
or adjustment. 

When assembling cannot be avoided for individual pieces, the parts may be 
so designed that the work of assembling is much simplified. This is done by 
making the parts lock into each other in such a manner that they cannot lose their 
adjustment and can readily be located in the proper position; for this purpose 
dowel pins on one part and corresponding holes in the other, or keys and keyways, 
tongued grooves, square holes, inter-locking lugs, etc., may be cast. Of course, 
the uniformity and accuracy of die-castings alone make assembling easy and inex- 
pensive. We have been advised frequently by customers that the accuracy and 
finish of "Precision" castings has made possible a reduction in their piecework 
rates, as well as permitting other economies necessarily incident to higher and 
more dependable production. 

Ouick Delivery Die-castings as a general rule cannot be made faster 
'^ than plain punchings or simple screw machine parts, 

but they are less liable to delays in production caused by lack of sheet metal of 
suitable kind or the needed sizes or shapes of rods or bars used on the screw ma- 
chines. But die-castings can always be produced much faster than similar parts 
can be sand cast and machined. Precision machines are capable of exceedingly 
high production. On long runs an average of over 300 operations of the dies per 
hour has been registered. 

As a rule less labor is required to produce a die-casting than any other pro- 
cesses would require for the same part ; consequently production is quicker and 
surer, because the die is virtually a positive automatic machine not subject to the 
errors of machine work. 

We have not yet met with a case in which our daily production was below 

12 



the daily capacity of our customer to use the parts, excepting of course Govern- 
ment orders placed during the war. 

When dies are once made, deliveries, when needed, may usually commence in 
a few days after receipt of order, dependent upon the amount of work involved in 
removing the gates and fins from the castings. 

C^OSt ^^^ things considered, a die-casting, when suitable, usually presents a 
cost advantage, but they are not always used for that reason alone. 
Intricate parts requiring a great deal of machining and finishing usually present a 
large saving. The die-casting process, generally speaking, is more expensive than 
sand casting, and for that reason sand castings that may be used without machin- 
ing or finishing operations cannot be die-cast to advantage. 

No idea of the cost of particular parts can be given, as this depends on the 
weight, design, and quantity ordered, as well as on the die equipment; quotations 
should be secured in each case. 

In considering the cost of dies it must not be forgotten that they offset the 
investment usually needed in other processes for patterns, jigs, fixtures and special 
tools. Furthermore, dies are not subject to the w^ear and deterioration of other 
tools, as they are kept by us in perfect condition without charge. 

MachininP" A.clva.nta.P"CS ^^ '^ frequently advisable to do machine work 

on die-castings when the machining opera- 
tions are inexpensive and the work of die-casting is thereby made simpler and less 
expensive. This Is true of Inside threads in most cases, and sometimes of Inside 
grooves, under-cut slots, etc. When machine work is done it is simpler and cheaper 
than the same work done on sand castings, due to the uniformity of the die-cast- 
ings, and the ease with which they may be located in jigs and fixtures. When 
holes are to be reamed or surfaces ground or machined less stock need be allowed 
and a lighter cut taken, due to the accuracy of the castings. 

Manufacturing Advantages ^^^ ^^^ manufacturing advantages 

cannot be enumerated because many 
are subject to the facilities of the manufacturer using them, and depend on the 
particular or peculiar problems involved in each case. 

A user of die-castings reduces and frequently eliminates labor troubles, he 
avoids idle tool equipment, as is the case when the work required of certain tools 
is not up to their yearly capacity. To the same extent he has no depreciation or 
loss on equipment. He requires less capital for plant, he uses less factory space, 
less light, less power, or releases them for other purposes. 

There are many hidden leaks and undiscovered losses in the average factory 
which run for long periods, resulting in some uncertainty as to what the actual 
cost of the work is. Die-castings, on the other hand, enable a manufacturer to 
secure his finished part ready for assembly at a definite, fixed, and dependable cost. 
13 




Envelope sealing machine, 
Zinc and lead alloys. 



14 



II. Cost and Suggestions to Purchasers 

Die-castings are sold at a price per piece or set of pieces, and the dies are the 
subject of a separate charge. The following factors of cost are considered in 
preparing estimates : 

1. Weight. 

2. Kind of metal used. 

3. Quantity ordered in one run or setting of the dies. 

4. Total quantity ordered. 

5. Casting production per hour. 

6. Cleaning operations required. 

Die-castings, as pointed out before, are not always cheaper than the same 
parts produced by other processes, as the production of casting machines is not high 
compared with screw machines or presses. A casting machine to be run efficiently, 
requires two operators and represents a high daily maintenance cost for power, 
fuel and metal losses. It is therefore principally the labor cost of non-automatic 
manufacturing operations that is reduced by the use of die-castings, such as ma- 
chine work of any kind, engraving, filing, fitting, grinding, spinning, bending, 
soldering, assembling, etc. 

Setting the dies and getting them started is slow and troublesome work. 
After the dies are started it takes some time before the men are familiar with them 
and get up to a high average production. New dies require a certain time to 
be broken in and "seasoned". For these reasons, the process is essentially a quan- 
tity proposition, permitting very low production cost in long runs ; but on the other 
hand in small quantities the cost is sometimes much greater than for the same pro- 
duction by other processes. Generally a thousand is the minimum lot, but very 
heavy and expensive parts are sometimes made to advantage in smaller quantities. 
Small and simple parts should be ordered in larger lots. 

The white metals used for die-casting are all more expensive than steel or 
iron and in consequence when a part may be made of these metals at small labor 
cost, the expense will be less than that of die-castings. 

Cleaning or trimming die-castings after they are made is an important item 
of cost. The gates must be removed and also the fins which appear around the 
parting line of the die, in holes and around the parting line of all moving parts in 
the die. This w^ork is sometimes difficult and tedious and if carelessly or cheaply 
done will detract from the appearance and accuracy of the castings or spoil them 
entirely. 

In large quantities, special jigs and fixtures or cleaning tools can be made to 
reduce this cost, but it nevertheless frequently amounts to more than the casting 
labor. In the Precision shops special attention is given to this branch of the 
work. We give each operation close inspection. We do not employ cheap labor 
for operations which require care or skill. The equipment used in our cleaning 
department is modern and accurate, many tools having been specially designed and 
built by us for work to which standard equipment is not so well adapted. 

Comparatively light and simple parts, when used in quantities large enough 
to justify the die cost, may be made in multiple dies running as high as fifty im- 
15 




Aluminum steering column sectors and levers, 
spark and throttle control gears, szvitcli keys, etc. 



pressions, according to the piece. The Precision process, due to the pressure and 
power of the machines and the die construction employed, permits the use of 
unusually large dies and the casting of a wide range of combinations in one mold. 
We sometimes make an entire machine consisting of seven or eight parts in a 
single combination die, thereby greatly reducing die cost as well as casting cost, 
since a combination die of eight parts would not cost as much as two die3 of four 
parts or four dies of two parts each. When combination dies are made, the parts 
should always be ordered in sets as it is not practical to make castings out of a por- 
tion of a die only. 

Except in very plain cases, the only way to determine whether or not a part 
may be die-cast to advantage is to submit it for estimate. 

16 



In comparing estimates it must not be forgotten that you are buying service 
and skilled labor and not a stock commodity. The workmanship and service of 
no two die-casting companies are alike, just as the service of no two doctors, or 
engineers, or architects is alike. 

The work of the Precision Castings Co., Inc., has its own individuality and 
character. It is turned out by an organization of the most skilled men in the 
industry. Every detail has been worked out to its logical conclusion, making the 
Precision product a finished product in every sense of the word. Our chief inspec- 
tor has assistants in every department who follow the work from beginning to end, 
preventing factory losses and delays and avoiding the production and shipment of 
defective parts. 

We have frequently heard it said that the lowest bidder is entitled to the 
order ; that he will be held to the specifications and the work returned if not found 
satisfactory. It is an error to assume that strict specifications may be made a 
substitute for good workmanship and service. 

The cost of applying specifications that are not respected, the manufacturing 
delays, the losses due to defects discovered only after work has been done on the 
castings, must all be added to the lowest bidder's quotation, unless he can demon- 
strate his ability and the high character of his product. 

It is our fixed purpose to keep Precision Die-Castings and 'the service back of 
them up to the highest commercial standards and quote the lowest prices that this 
policy will permit. 

Estimates are prepared from models or blue prints, preferably models, or both 
when the model is not accurate. In die construction, when both models and prints 
are submitted, we follow the prints if there is any difference. When any doubt 
exists as to the suitability of the metal we propose to use, it should be thoroughly 
tested. We will furnish ingots for this purpose from which the parts to be die- 
cast may be poured in sand and machined to size. If the parts are found satisfac- 
tory, our die-castings will be found even stronger and better, due to the added 
strength given by the pressure and rapid chilling in the dies. 





Aluminum pump shaft housing cover. Liberty motor. 



17 



The information given when orders are placed or estimates requested, should 
be as complete as possible. We suggest that the following points be given con- 
sideration and that we be advised fully concerning them : 

1. Electrical conditions under which the parts will be used. 

2. Temperature conditions — will they be subjected to heat 
or cold. 

3. Will they be used indoors or out. 

4. Will they be subjected to hard shocks, strains or wear. 

5. If there are bearing surfaces under what loads and speeds 
will they operate. 

6. Will the parts come in contact with water, moisture, 
gases, or corrosive liquids. 

7. Will they come in contact with foods. 

8. Will the parts be finished — if so, how (plated, baked 
or cold enameled, polished, etc.). 

9. How will the parts be assembled and used. 

10. When several parts are submitted they should be num- 
bered or named to avoid confusion. 

11. If they must fit other parts not furnished by us, such 
parts should be furnished, with suitable gauges and the 
kind of fit specified. 

12. If several parts are wanted, will they always be ordered 
in sets so that they may be made in combination dies. 

13. Between what points, if any, is special accuracy required. 

When a complete model or an assembly print of the device in which the parts 
will be used can be furnished, it is always best to do so, as most of the information 
needed is usually conveyed by the model itself. New inventions or devices or 
designs not yet published or on the market will, of course, be treated as confiden- 
tial. 

New devices should be thoroughly tested and exact models built before the 
dies are constructed, as it is sometimes expensive and difficult to alter dies. 

Our wide experience in applying the use of die-castings to every field in which 
they are used, makes the services of our engineering department very valuable to 
our customers. Our engineers will gladly assist in the design of parts and prepare 
sketches or drawings embodying their suggestions. Their advice on the latest and 
most approved methods of handling, finishing, assembling and machining die-cast- 
ings will be found of valuable assistance. 




Aluminum mold insert for cord tires. 



III. Metals 



Conditions which Restrict 
the Selection of Metals Used 



The process is such in its very 
nature that only a very limited 
number of alloys can be die-cast 
commercially. Such metals must 
have a fusing point and shrinkage which will not be so great as to injure or destroy 
the metals of which the dies and casting machines are made. 

The molten metal to be die-cast must be held in a compression chamber and 
subjected to high pressure. Aletal must be used for the compression chamber, 
since no other material has the required strength and wearing qualities at the 
necessary working temperatures. 

Metals when molten have a tendency to alloy with other metals coming in 
contact with them, even though such metals are far below their fusing tempera- 
ture. For instance, molten zinc in an iron pot will eat away part of the iron 
and gradually destroy the pot. The dissolved iron forms an alloy with the zinc 
and after an excessive amount of iron has been absorbed, the zinc becomes unsuit- 
able for use. The metals which may 
be die-cast are therefore first limited 
to those which may with practical 
results, be handled in metal pressure 
chambers and dies. 

The degree of pressure applied has 
a marked effect on the grain and qual- 
ity of the work. Pressures applied by 
the Precision process vary from 200 to 
1000 pounds to the square inch, ac- 
cording to the work to be produced. 
The casting or pressure chamber must 
therefore have a high tensile strength 
at temperatures ranging between 800° 
and 1300° F., the points between 
which die-castings are poured. 

The velocity at which metals enter 
the dies is tremendous, and at the 
temperature used will quickly destroy 
dies made from poorly selected metals 
or not properly treated and prepared. 

The shrinkage of castings in the 
dies subjects them to great strain and 
wear. This problem does not exist 
when casting in sand, as in that case 

D , ^ , ■ . . ^ J. the metal in shrinking carries the 

raris for motors, instruments, cameras, stamp ^ 

affixers, etc. Aluminum, tin and zinc alloys, mold with it. 




19 




Phonograph clboivs, tour arms 
and sound boxes. Zinc alloys. 



The metal to be die-cast, when solidifying, must have a certain amount of 
elasticity, as otherwise in shrinking against cores in the die, it will crack. 

Aluminum alloys subject the portions of the dies against which they shrink 
to great wear, as they have a high shrinkage and fall substantially below their 
fusing point before being removed from the dies. It is apparent, therefore, that 
when the shrinkage and tensile strength of the metal to be die-cast exceeds a cer- 
tain point, no die material may be found which will withstand the strain. 

Another important consideration in determining the metals which may be 
die-cast, is the necessity' of maintaining the metal continuously in a molten state 
in the machine or in an adjacent crucible. In some metals this causes excessive 
oxidation and occlusion of gases and impurities, resulting in porous, imperfect 
castings of low tensile strength. 

20 



This condition does not exist in sand molding, as the molds are first prepared 
and the entire pot of metal then poured in a comparatively short space of time. 
The die-casting machine operates onl\ one mold, but works it continuously, requir-. 
ing that a given quantity of metal be constantly in readiness for casting. 

The metal formulas used by us are the result of long study and many experi- 
ments, as well as of our observation of die-casting metals in use over a long period 
of years. There are a great many important considerations which govern these 
formulas and guide us in the selection of the metals used for anv particular work. 
These considerations involve the conduct of the metal in the casting machines 
almost as much as the strength and lasting qualities of the castings. Strong, solid 
and accurate castings cannot be produced from metals which by reason of their 
sluggishness, shrinkage, fusing point, tendency to dross, brittleness at high tem- 
peratures below fusing, etc., seriously interfere with production in the casting 
machines. 

For these reasons it is very important that the formula be strictly maintained. 
This is not an easy matter when metals are kept in a molten condition for long 
periods due to their tendency to separate in layers according to their specific 
gravity. 

While the molten metal is in the casting machines we constantly stir it bv 
means of a device attached to the machine, keeping the formula constant and 
bringing oxides, gases and impurities to the surface. 

Up to this time the difficulties involved in casting brass, bronze, iron, steel, 
nickel alloys, etc., have stood in the way of the successful commercial application 
of the process to these metals, although it is not unlikely that in the next few 
years brass die-castings will be produced commercially. 



Y)'lQ C^astinp" AlloVS ^^^^ tables on p. 83.) The Precision Castings 

Co., Inc., maintains a laboratory in charge of the 
chief chemist, who also supervises the foundiy in which all metals are mixed. He 
or his assistants, personally check up all weights before the metals are mixed to 
prevent variations in formula. All metals used in the foundry can be obtained 
from stock only on the chief chemist's requisition. The strictest supervision in 
maintained to avoid the production of inferior metals, either through insufficient 
or too much heat, and the temperature of all molten metals is constantly watched 
with pyrometers. 

Our laboratory is specially equipped for the testing and treatment of white 
metals, and the men in charge have the advantage of many years of experience in 
this particular work. They employ the best methods for refining metals and know 
the sequence to be followed in combining the alloys. Pouring temperatures are 
carefully watched and the proper fluxes and de-oxidizers used. There can be no 
question, therefore, that the results obtained are the best that experience and 
modern science make possible. 

Excessive impurities in die-casting metals are very harmful and also greatly 
reduce and hinder production. We use onh- the purest metals suitable for the 
21 



work. All metals are analyzed for impurities before acceptance, and rejected if 
they exceed our specifications in any particular. For this reason when metal cost 
is an important factor, we cannot always compete with concerns using the ordi- 
nary or low grade metals, although in many cases our manufacturing methods and 
equipment enable us to overcome this cost difference. 

Alliminiim AlloVS The most satisfactory aluminum alloys die-cast are 

those generally known in the trade as aluminum- 
copper allocs and contain from 5'/' to 20% copper. Aluminum-copper alloys are 
stronger and harder than pure aluminum and are more easily finished and ma- 
chined. The tensile strength of our die-cast copper-aluminum alloys runs between 
18,000 and 21,000 lbs. to the square inch. 

The high compressiv'e strength of the copper-aluminum alloys is due to the 
formation of a needle-like eutectic (AU cu. and Al.) which is imbedded in prac- 
tically pure aluminum. They have nearly the same general chemical properties 
as pure aluminum. 

Comparative figures of the properties of sand and die-cast No. 12 alloys 
(92% Al. and 8'/( copper), show that the die-casting has 20% more elastic limit 
and almost double the percentage of elongation. 

The addition of copper to aluminum, besides increasing the tensile strength, 
reduces the fusing point and shrinkage, making the metal more suitable for die- 
casting. 

In die-casting aluminum it is not always practical or desirable to hold to any 
particular copper content, but this may be increased or reduced as the casting con- 
ditions warrant. Die-castings may be made with satisfactory results with as much 
as 21% or 22% of copper, when the design of the piece or its functions require. 
More than 23% copper is rarely, if ever, used. When casting in sand more than 
8% or 10% of copper is not frequently used, as the slow cooling permits the 
formation of large crystals and in consequence produces a brittle metal. The 
rapid and almost instantaneous chilling which takes place when these alloys are 
die-cast prevents the formation of large crystals and therefore produces a very 
much tougher metal. 

Zinc strengthens aluminum more than copper or manganese, but it is not 
suitable for die-casting as the high temperature at which the metal must be main- 
tained for extended periods causes it to burn out and dross excessively, destroying 
the good qualities of the alloy. These metals should only be used under condi- 
tions which permit immediate pouring after melting. 

The presence of zinc in aluminum-copper alloys causes a great number of the 
needle-like eutectic to be thrown out, so that the copper content must be decreased 
as the zinc is raised. Eurojjean practice has favored these alloys over the alumi- 
num-copper, owing to their somewhat greater tensile strength, but in American 
practice the zinc is generally omitted. It has been asserted that zinc-copper- 
aluminum alloys fail in time under stress, but this has not been satisfactorily 
proven. They should not be die-cast because of the drossing of the zinc. In 
saline solutions, galvanic action causes such alloys to deteriorate rapidly. 

22 



Tin has never been a satisfactory metal for use in conjunction with aluminum 
in die-casting. It makes the metal too brittle, its brittleness increasing in time, 
and the alloy is not as strong. As tin is also expensive it is rarely used. 

Manganese-aluminum alloys may also be used, but unless used for special 
purposes they present no substantial advantage in strength or general commercial 
qualities over the copper-aluminum alloys. 

Under normal markets aluminum, though comparatively high in cost per 
pound, is really no more expensive than the cheaper white metals, due to its low 
specific gravity. For instance, a casting weighing one pound in No. 12 aluminum 
alloy will, if made in the following metals, have these weights : 

Copper 3.2 lbs. 

Brass 3.0 " 

Cast Iron 2.6 " 

Lead 4.0 " 

Zinc 2.5 " 

Bronze 3.1 

Lead and aluminum do not "mix", having no affinity for each other. Lead 
is a harmful impurity in aluminum, but can only be present in very small amounts 
as the metal will not "hold it". Tin in aluminum-copper alloys is harmful. It 
causes excessive brittleness in time and the castings will disintegrate. Not more 
than \y2'/( to 2% of iron should be present in aluminum alloys as otherwise the 
metal will become too brittle. Below that amount iron is not harmful. 




Alumiuiim brush holders for electric motors. Electric instrument frames, tin olloys. 



23 



Properties of Pure Aluminum ^"''^ aluminum is not generally 

used for castings because it is 
softer and more porous than its alloys. Its strength and hardness are considerably 
increased when it is compressed or rolled. It may be rolled in sheets .005" thick. 
Gold alone is more malleable. The metal has excellent tonal qualities which are 
improved by the addition of silver. 

The electrical conductivity of the pure metal is about 62 in the Matthiessen 
Scale. It is practically non-magnetic and is an excellent conductor of electricity. 
It is sometimes used for power feeders and high tension transmission lines. 

Its heat conductivity is greater than zinc, iron, tin or steel, and is exceeded 
only by copper among the baser metals. 

The specific gravity of ordinary grades is 2.68, making it about ten twenty- 
sevenths the weight of cast iron. 

Shrinkage per foot is .2031". Its linear expansion is exceeded among the 
common metals by zinc and lead only. 

Aluminum melts at 657° C. or 1215° F. and develops weakness at solidifica- 
tion tending to cause cracking, due to the absorption of oxides, silicates, and other 
impurities, and its high shrinkage. 



Chemica.1 PrOOertieS ^^^^ natural solvent of aluminum is hydro- 

„ . . chloric acid. It is slowly attacked by either 

OI /\lUminum concentrated or dilute sulphuric acid, but the 

hot concentrated acid dissolves it readily. Cold 
dilute or concentrated nitric acid have little effect and act but slowly when hot. 
It is not affected by sulphur at less than red heat. 

Organic secretions and salts have little effect, and vinegar (4% acetic acid) 
practically none. For this reason it is sometimes used for dental plates and surgi- 
cal instruments. The acids in foods have little effect and when any action takes 
place the chemical products are harmless, which makes the metal well suited for 
kitchen ware. 

Contrary to an impression frequently held, it is not affected by mineral and 
sea waters. Strips of aluminum were placed on the side of a wooden ship and 
were found to be corroded less than .005" after six months exposure to sea water, 
whereas copper under the same conditions corroded nearly twice as much. 

Aluminum may, however, be made to corrode rapidly in salt water by being 
held in contact with another metal such as copper or iron, causing galvanic action 
to take place. 

As most metals are electro-negative to aluminum, a voltaic couple is formed 
under such conditions, resulting in the rapid corrosion of the electro-positive 
metal. When, therefore, aluminum is used under such conditions, it should be 
insulated from the electro-negative metals with a good insulating material such as 
rubber, or a heavy coat of insulating paint. 

Aluminum is not attacked by carbonic acid, carbonic oxide, or sulphuretted 
hydrogen. 

24 




A eroplane speedometer made for 
the U. S. Government. Aluminum. 
Measures speed by wind velocity. 



Aluminum has been said to absorb nitrogen from the air, causing it to deter- 
iorate, but experiments recently made have proven that the metal does not absorb 
any nitrogen bubbled through it for several hours, although it may under such 
conditions retain a minute trace to no harmful extent. 

Solutions of caustic alkali, bromide, chlorine and hydrofluoric acid attack the 
metal quickly. 

The common impurities are silicon and iron. Aluminum has a great affinity 
for iron, being in the same chemical group. Impurities in excessive quantities 
materialh' reduce the resistance of the metal to corrosion. 



2^inC A-lloVS ^^^^ tables, p. 83.) Zinc alloys containing various propor- 
tions of tin, copper and aluminum or only one or two of these 
metals, have been used since the inception of the die-casting industry. They are 
comparatively cheap among the white metals, but considerably more expensive 
than cast iron, which they resemble in strength and brittleness. 

Precision zinc alloys vary between 12,000 to 16,000 lbs. tensile strength to 
the square inch, according to the design of the part and formula used. 
25 



They ma}' be plated, finished and machined as described under separate 
headings. They should not be used for food containers, and are corrosive in con- 
tact with moisture. They should not be used under heat conditions exceeding 
about 150° F., but may temporarily be subjected to between 250° F. and 300° F. 
according to the formula. 

Pure zinc is too brittle and soft to be die-cast and flows sluggishly. When 
alloyed with tin, copper or aluminum the crystals are materially reduced, produc- 
ing a finer grain and a much tougher and stronger metal ; its shrinkage is also 
thereby reduced and it flows more readily. The rapid chilling in the die greatly 
increases the strength and toughness of the metal. 

Tin alone does not increase the tensile strength or hardness but softens the 
metal, makes it flow more readily and prevents a certain amount of shortness or 
cracking. In excess of about 8% it performs no useful function and does not 
combine well. 

Copper toughens and strengthens the metal but should not be added over 
3/^%, as then it increases the fusing point to such an extent that excessive dross- 
ing and oxidation are caused in the casting machines. 

Aluminum is a wonderful de-oxidizing agent, reducing the dissolved or im- 
prisoned oxides within the metal and forming alumina which floats on the surface 




Upper center and loiver left, s-ci-vel joints for flexible speedometer 
shafts. Other parts instrument and speedometer frames. Zinc alloys. 



26 



and is skimmed off. It is also valuable because it forms a very thin coating of 
aluminum oxide on the surface of the die-casting which prevents the alloA' from 
soldering or sticking to the dies, due to the affinity of zinc for iron. Aluminum in 
small percentages also makes the metal flow more readily and its de-oxidizing 
qualities strengthen and toughen the alloy. More than yS % of aluminum should 
not be added in zinc alloys containing tin, as this will cause deterioration. (See 
last paragraph below. ) 

All metals when molten have a tendency to absorb atmospheric and fuel 
gases; oxides also are occluded and held mechanically within the metal. This 
latter property is well illustrated in the thick scum on the surface of zinc alloys 
before fluxing, which consists of an intimate mixture of metals and oxides, and 
rises to the top because of its lower specific gravity. To free the metal from 
oxides the most suitable flux used is sal-ammoniac. This decomposes into ammo- 
nia and hydrochloric acid ; the volatile chlorides free the metal from the oxides 
and the clean oxides are then skimmed off the surface. 

PrODertieS of Pure Zinc Zinc, or spelter as it is known in the trade, 

is a bluish white metal, hard and brittle 
and coarsely crystalline when the pouring temperature is much above the melting 
point, but more granular when poured near the melting point, which also makes 
it more malleable and more resistent to acids. Rapid chilling greatly reduces the 
size of the crystals. 

In dry air, pure zinc retains its lustre, but moisture causes it to become cov- 
ered with thin greyish white coat of basic carbonate which protects it from further 
corrosion. Pure zinc in sheet form was exposed on a roof in Bavaria for 27 years 
and showed oxidation of only .004". 

In the presence of impurities or \\hen cast with other metal, it loses its non- 
corrosive qualities to greater or lesser extent, according to the circumstances. 

It is not blackened by hydrogen sulphide fumes or solutions as are copper, 
silver, lead, etc. It dissolves readily in nitric acid, but when pure is almost insolu- 
ble in other acids. Ordinary zinc (prime western grades) will dissolve in 
hydrochloric (muriatic) and sulphuric acids. Caustic alkalies dissolve it more 
slowly. 

With the exception of aluminum and magnesium, zinc is the most electro- 
positive of the common metals. In consequence it is easily dissolved when in the 
presence of caustic alkali and in contact with electro-negative metals, such as iron, 
tin or copper, all of which are below aluminum in the electro-chemical series. 
(See table, p. 86.) A high percentage of aluminum in the zinc-tin-copper alloys 
is undesirable for the same reason. Under these conditions a voltaic couple is 
formed, resulting in the immediate and severe attack of the electro-positive ele- 
ment by the electro-motive force produced by the difference in potential or chemi- 
cal action of the negative and positive metals. 

It is for this reason that zinc alloys containing copper, tin and aluminum are 
corrosive in the presence of moisture. By care in the preparation of the alloy 
27 



this corrosive action may be reduced. With this end in view, alloys of zinc made 
up in the Precision laboratory are very low in impurities and when tin and alumi- 
num are both present the aluminum content is held to very low limits. 

T^-p«-j, j^|-|-jpo j|-j 7{t\C Low grade spelters should not be used when the 

quality of the die-casting is a consideration. 

They affect the lasting qualities of the metal, weaken it, and produce a poor finish. 

The common impurities are lead, iron, cadmium and arsenic. Under the 

proposed revision of standards as of March 8, 1917, the American Society for 

Testing Materials divides spelter into five grades as follows: 

% % Vc Total 

Lead Iron Cadmium % not over 

High Grade* 0.07 0.03 0.07 0.10 

Intermediate* 0.20 0.03 0.50 0.50 

Brass Special* 0.60 0.03 0.50 1.00 

Selected* 0.80 0.04 0.75 1.25 

Prime Western 1.60 0.08 

*It shall be free from aluminum. 

Cadmium over .30*/^ makes the metal short, and causes cracks in shrinking. 

Lead is not as injurious as cadmium, arsenic or iron. Zinc cannot hold 
more than 3% of lead except when liquid. At 788° F. it will hold 1.7% and at 
1200° F. 5.6%. Lead should not be present in zinc die-castings over 1%. 

Iron above .13'/ tends to make the zinc brittle. In substantial proportions 
it makes the metal easily reducible to a fine powder. A certain amount of iron 
cannot be kept out of die-castings, as the metal is absorbed in the pots of the 
machines. 

Arsenic over .05% has the same effect as iron and in large proportions, due 
to its great affinity for iron, will cause the metal to attack the iron pots and parts 
of the die-casting machines more rapidly. 




Bouchon for hand grenades. 
O^er 25,000,000 madtt for 
the U. S. Go--cernment. 



28 




Babbitt bushings. 



Tin AlloVS (See tables, p. 83.) Tin when die-cast is usually combined 
with varying proportions of antimony, copper and lead or 
only one or two of these metals. It may also be cast pure. Tin alloys are not 
brittle, they have low tensile strength but are easy to cast because of their low 
fusing points and the fact that the metal flows readily in the dies. Very small or 
delicate parts which cannot be cast in zinc or aluminum alloys are for that reason 
often made in tin alloys. Their low shrinkage makes them more accurate and 
largely avoids cracks in casting. 
29 



They are not corrosive in the ordinary acceptance of the term and may be 
used for parts coming in contact with food when no lead is in the alloy. They 
are not affected by moisture and are slowly affected by alkalies and mineral acids. 

(^ne of the chief uses for the tin alloys is in the composition of bearing or 
anti-friction metals known as babbitts. 

T ead AlloVS ^^^^ table, p. 83.) Lead is usually alloyed with tin and 
antimony ; in substantial proportions it will not readily 
allov with c(jpper, except in the presence of tin and antimon\ , and at a tempera- 
ture and under conditions which render it impracticable for ordinary uses and 
particularly for die-casting. 

Lead alloys should never come in contact with food, as organic acids react 
with them, forming basic lead salts which are poisonous. They are insoluble in 
dilute sulphuric acids, dissolve slowly in hydrochloric, and readily in nitric acid. 
They are not affected by moisture and are non-corrosive in a commercial sense on 
exposure to the elements. 

They are cheaper than the tin alloys, but not nearly so tough. They have 
similar casting properties and are greatly toughened by the rapid chilling in the 
dies. 

T\ pe metals all have a lead base and are made to various formulas according 
to the requirements. There is no standard type-metal formula and when used 
outside the printing trades it is usually understood to contain merely lead, hard- 
ened with antimony. One class of type metals used for printing contains : 

Lead 77% to 53% 

Antimonv 1%% to 26% 

Tin 5% to 18% 

Copper to 3% 

The metal used in linot\pe machines contains about: 

Lead 83% 

Antimonv 14% 

Tin :. 3% 

A j-j4-i_p-t-ip-j-jQj^ (See tables, p. 83.) In a perfectly adjusted and 

i.r 1 -Q L L • lubricated bearing, there would be a thin layer of oil 

Metals or babbitts 5^^,^,^^^ the journal and the bearing; the metals 

would not actually touch each other at any point and 
the friction would not be between the metals themselves but between the metals 
and the film of oil. Such a perfectly adjusted bearing is never attained in prac- 
tice and the purpose for which babbitts are designed is to overcome the harmful 
effects which are brought about by actual metallic contact between the journal 
and the bearing due to the necessarily inaccurate and uneven surfaces. 

This is done in two ways; first, by making the body of the bearing metal 
plastic enough to conform to the inequalities in the journal, thereby fitting itself 
as perfectly as possible ; and second, by making the bearing surface as hard as possi- 
ble to reduce friction and wear. 

30 




Babbitt bearings for combustion motors. 
31 



The softer a metal, the greater is its co-efficient of friction. Hard metals 
require greater pressure to produce the same friction as soft metals. 

Hence alloys containing hard crystals imbedded in a plastic matrix answer 
the general requirements of most bearing metals, the hard cystals reducing the 
frictional contact, and the body or matrix adjusting itself to the size of the jour- 
nal. 

A representative babbitt formula is: 

Tin 89.1% 

Antimony 7.2% 

Copper 3.7% 

In this and similar metals two groups of metallic compounds are formed, one 
of tin and antimony corresponding to the formula Sn Sb (49% tin and 50% 
ant.), and the other of tin and copper, corresponding to the formula Sn Cus and 
Sn Cu (Sn Cu;; — 38.5 tin to 61.5 copper), and ( Sn Cu — 55 tin to 35 copper). 
These compounds form the hard crystals which furnish the anti-frictional quali- 
ties of the metal. 

By adding a small percentage of aluminum, babbitts are made considerably 
closer in grain, resulting in greater durability and wearing qualities. The rapid 
chilling in the mold when die-cast also toughens and strengthens the metal to such 
an extent that hammering or compressing the bearings is unnecessary. Bearings 
poured in hot molds or not chilled are considerably softer, and to give good 
results must usually be compressed before they are assembled in a combustion 
motor. The general practice is to set them up and run through an expansion 
roller. If this is not done such bearings will compress in service, leaving too 
much clearance between the bearings and the shaft. 

For many purposes, when pressure is light, antimonial lead alloys are among 
the best bearing metals known. Combined in the proportion of lead 87% and 
antimony 13% a eutectic is formed which is four times as hard as lead. When 
the antimony content is raised, crystals of free antimony are held within the 
eutectic, and when these crystals become numerous enough to come in contact with 
each other, the load on the metal, instead of being transmitted through the eutec- 
tic, is taken up by the antimony crystals, and the metal is too brittle for use. This 
is the case when more than 23% is used. 

Copper up to 21^2% will raise the fusing point of such alloys and toughen 
them. Tin may also be added which will reduce the fusing point and toughen 
the metal. When high pressures are encountered, tin is a desirable element up to 
\0'/( , reducing brittleness and lending rigidity to the bearing. Lead bearing 
allo\s, when used for heavy loads or under conditions which develop heat above 
about 250° F., should not contain more than 10% of tin, as more than that will 
reduce the fusing point and cause "squeezing out" when the bearings run hot. 

We have manufactured babbitt bearings for the largest motor builders for 
years, having grown up with the automobile industry. "Precision" bearings are 
favorably known wherever motors are built. Our metallurgical chemists and 
engineers have succeeded in producing a series of babbits of various grades which, 

32 



while equal to the finest babbitts made for the general trade, are at the same time 
designed so that they will be toughened and hardened more by the die-casting 
process we subject them to, than ordinary metals. 



Ball bearing retainers 
and babbitt bearing shims, 
tin and zinc alloys. 




33 




Precision Castings Co.'s die shop in Fayetteville plant. 



IV. Dies, Die-Design and 
Construction 

Die-casting dies probably present more difficulties in design and workmanship 
than any other dies. Their life depends entirely on their construction, the char- 
acter of metal used both for the die and the castings made in them, the design 
of the piece to be made, the care they receive, etc. Naturally, a die for a delicate 
piece, having many moving slides and cores, w^ill not last as long as a simple die 
under the same conditions. The important part which workmanship and material 
play in the life of a die, as well as in the quality of its product, cannot be empha- 
sized too strongly. The wise buyer will never question a die charge if other 
factors are satisfactory. Some dies are good for 25,000 castings, others for a mil- 
lion. Precision dies are built for endurance irrespective of expense, as we are 
equipped especially for quantity production and consider the best dies the cheapest 
in the end. We shoulder a large part of the die cost ourselves to avoid any 
tendency on the part of customers to save unwisely in such expenditures. 

■ , 34 



realises of Tnarnirarv Although design and construction have a most 

important bearing on the accuracy, finish, and 
in Lja.Sting'S grain of the castings, it is frequently very diffi- 

cult to determine whether defects in castings 
are due to dies or other causes. 

Inaccuracy may be due to a number of causes. If constant, i. e., alike in all 
castings, it is almost always due to an error in the size of the die, or a shifting or 
warping of the die parts. 

Precision dies are cut from solid blocks whenever possible. This is often 
more expensive than "building up" an impression but it is much more satisfactory 
in results. Many constructions, due to the design of the part, must be "built up" 
out of several pieces and in such work the greatest care should be used. 

Molten metal under high pressure will creep into the slightest crevices. All 
die parts must therefore be perfectly fitted. The high pressure and hard w^ear to 
which they are subjected require substantial construction. Long practical exper- 
ience is necessary to properly direct work of this kind. 

The heat at which dies are worked and the constant heating and cooling 
which take place will cause them to warp badly if steps are not taken to overcome 
this. For this reason all dies are heat-treated to take all the internal strains out 
of the metal and protect its surfaces from the destructive action of the molten 
metal. 



Pulley Wheel Die. Part cast from it shown in 
center. The belt groove is formed by two slides, 
shown in open position. The slides are operated 
by a single lever as shown. The dowel pins shown 
on left die-plate pass through the slides when closed 
and hold them firmly in position for the casting 
operation. 




35 




Number Wheel Die. Engraving; is formed on the 12 slides. These 
slides are fastened to rollers which travel in the cam slots in the circu- 
lar plate, back of the slides. By moving; the lever attached to the plate 
back and forth the slides are withdrawn or put in place. The plate on 
the extreme left fits over the slide mechanism to protect it. The die is 
g;ated throug^h the center, a sprue cutter beings used. 



When inaccuracy varies in different castings of the same run it may be due to 
a number of causes. If the error is across the parting line it may be due to par- 
ticles of dirt or metal on the die surfaces, holding them apart. In old style cast- 
ing machines it may be due to wear in the clamps and toggles used to hold the dies 
shut, or to their weakness. When a casting is made, the pressure under which 
the molten metal enters the die has a tendency to open the dies and when large 
castings are made the strain on the dies is great, running as high as 15 tons. 

Precision power driven die-casting machines do not use clamping devices and 
are not dependent on mechanical means to keep the dies closed. They are held 
shut under much greater pressure than is exerted to open the dies, so that there is 
no likelihood of undue variation from this cause in our work. 

Undue variation in die tempearture, especially in large parts, also causes 
inaccuracy. There are a number of features in our process peculiarly suited to 
die temperature control in that the operation of the machines is constant and 
steady, the die position fixed and temperature fully controlled. 

Precision dies are water-cooled and their temperature control lies in the 
means of regulation used to control the flow of water, but if the operating condi- 
tions are unfavorable, such as irregular operation and heats, temperature control 
is useless. 

36 



If moving parts of dies are cheaply constructed through a desire to save time 
or material cost, or through inexperience, a great many difficulties may beset the 
way of the user as well as the producer of die-castings. Metal pressure may open 
or shift cores. If they are not properly fitted and lubricated wear will result, 
causing inaccuracy. 

Dies should be so constructed that they may easily be taken down and thor- 
oughly overhauled and cleaned after a certain period of use. 

"r)jp A gcpppkly Each die is complete in itself and holds all the operating 
mechanism needed for its use. Attached to the ejector pin 
side of the die is an iron box, in which are mounted core and ejector pin plates 
which are operated by rack and pinion. Separate slides and cores are mounted on 
the die according to the design of the part to be made and are operated with han- 
dles or gears. They are usually fitted with safety devices to prevent improper 
operation, and locks to prevent their being moved by the metal pressure. 

Die Slirfa.CeS ^^^ ^^^ surfaces coming in contact with molten metal must 
be polished for finish and to prevent the castings from ad- 
hering to the dies. All surfaces rubbed by the castings in ejection can have no 
tool marks or depressions and must be absolutely smooth and slightly tapered to 
free the casting the moment it begins to move out. The amount of taper depends 
on the circumstances in each case (see page 52). Theoretically a casting could be 




Parts of die for aluminum steering; column sector. Extreme 
left cast iron die-box with pinion which operates ejector pin 
plate shown next. Next is the plate throug^h which the ejector 
pins pass and on the extreme right is shown the other die-plate. 
Below this is the core mounted on bracket with operating han- 
dle, which forms a hole in the casting. The casting as it comes 
from the die is also shown. 



37 




Die block in process on millings machine. Below is shown wood pattern of the part to be 
made. Note that the die impression is being milled out of a solid piece of steel instead of 

being- built up in sections. 



withdrawn without draft but in practice it is impossible to maintain an absolutely 
true surface w^ithout warpage. The slightest undercut will crack the casting in 
ejection. 

Cja.tinP" "^"'^^' S'lt^i'ig "f castings is the subject of constant study and no fixed 
rules can be applied. Castings, according to their size and design, 
are affected by the width, thickness, shape and location of a gate as well as by the 
direction in which it enters the casting. Improper gating will cause poor finish 
and porous castings. 

Die N4a.tGria.ls ^"'" '^''^' ^'"^ '^'^'^ le^d parts the die impression is made of 
machine steel. Except for special purposes it should not 
be hardened as the expansion and contraction will cause it to crack and check. 
Cast iron is seldom used for die impressions because its porosity has a tendency to 
make castings stick to it and show poor finish. It is not as easily worked as soft 
steel and cannot be bobbed. 

Drill rod and tool steels are used for ejector pins and cores, slides, etc. Soft 
machine steel cannot be used for aluminum. We have developed several special 
alloy steels for aluminum dies which have given wonderful service. In several 
instances over 200,000 castings were taken out of a single die. 

Shrinkage Allowance in Dies Shrinkage of castings is allowed 

for in the dies, so no allowance 
should be made in drawings or models. When simple pieces are made this allow- 
ance may be calculated accurately. The shrinkage of complicated pieces is held 

38 



back by portions of the die against which they shrink and the amount of shrinkage 
in many such cases can only be approximated. Long experience develops great 
skill in this respect and by working "safe", that is so that by taking a little more 
metal from the die any inaccuracy may be overcome, wonderful results are ob- 
tained. 

Cha.nP'eS Changes in dies may be made but it is best to av(jid them as much 
as possible. The die is the exact opposite of the part to be cast, 
therefore, to add metal to a part it need only be taken away from the die, but 
when on the other hand it is necessary to add metal to a die, the task is frequently 
a difficult one. It may be done b\ inserting pieces in the form of plugs or strips, 
but it is not practical to weld pieces to a die-impression. Changes frequently 
weaken the die construction or compel the use of inferior methods of die construc- 
tion, which could of course be avoided if the die had been laid out for the final 
design in the beginning. 

It is much better to take the time to build models and thoroughly try out all 
changes or new designs before building or changing dies. There should be no 
element of experiment in the production of die-castings as the process can only be 
used economically for quantity production of identical parts, and the dies should 
be used as first designed. 



«i>~ .'^^ ^'^^ 














"t 



Assembled die and plate 
made from it. Zinc alloy. 



39 



C^rOSsinP" and Inter- ^^ ^^ better practice to avoid cores or slides which 

■I Ul r^ P^^^ through each other. A small core passing 

changeable (^OreS through a large core is apt to strike the larger 

core, raising a burr, or injuring one or the other 
core. This will occur if the smallest particle of dirt prevents the larger core 
from taking its proper position. When the design cannot be modified to avoid 
die construction of this kind it is usually better to machine or drill that part of 
the casting which requires the undesirable die construction. 

When two or more parts of the same general design, but differing only in one 
or two details are wanted, it is frequently possible to make them from a single 
impression by using interchangeable plugs or cores in the die. 

r^Qiy»Kjpnt-JQrj F)ieS When combination dies containing two or more 

impressions of different parts are used, it is not 
good practice to shut off any of the impressions so that only certain ones may be 
cast, but the entire set must always be made. For this reason such dies should 
not be made unless the parts will always be used and ordered in complete sets. 




Die maker 
"Checking 

up." 



40 



RemOVa.1 of Dies l^recision dies are not removable although they are 

held for the exclusive use of the customers to whose 
order they are made and who pay part of their cost. We include only a portion 
of the die cost in our die charge. The rate charged is less than the actual hourly 
cost of the work to us. We assume full responsibility for the perfect condition of 
the dies perpetually without charge, except when changes which affect their de- 
sign are ordered by the customer. We also provide for insurance and assume all 
the risk. 

The design of Precision dies involves skill and experience, the result of 
many years of effort which we do not wish to make generally available. They 
are also best fitted for use on Precision machines and if used elsewhere would 
require material changes, which might produce wholly unsatisfactory results. Dies 
are easily injured in shipment or when handled by inexperienced workmen, owing 
to their delicate mechanism and heavy weight. 

The removal of dies is not permitted by the leading concerns in the die-cast- 
ing industr}^, and in other fields such as forging, stamping, rubber and composition 
molding, etc., a similar custom prevails. 

The dies represent an investment on our part which will be useless to us 
without the good will and patronage of those for whom they were built, and it 
must always be our aim to make Precision Service high in its standards and at- 
tractive in cost (as has been our practice for many years), if the business of the 
company is to continue to grow and prosper. 




Handles and knobs. 
Aluminum and zinc 

alloys. 



41 



V. Die-Casting Design 

Die-castings present entirely different problems in designing the parts to bet- 
ter adapt them to the process of manufacture than do sand castings, forgings or 
machined parts. Slight variations in construction or design frequently greatly 
reduce the cost and increase the strength and efficiency of the parts without inter- 
fering with their functions. Only those who have a very wide and thorough 
experience in the art of die-casting, combined with a good knowledge of mechani- 
cal and production engineering, can take full advantage of the possibilities the die- 
casting process offers in these respects. 

Among the numerous illustrations in this book are many in the designing of 
which our engineering department has lent valuable aid. This part of our service 
is always at the command of our customers. 

Walls Yir," and in some cases Y^i" thick may be cast, depending on the size 
and design of the parts and the metals used. The weight in zinc and tin should 
not exceed about 10 pounds, in lead about 15 pounds, and in aluminum about 3 
pounds. The average size depends on the piece but seldom exceeds 24" over all. 

Strains and stresses on parts should be studied and met by proper thickness 
of metal and wall construction. Inserts, beads, fillets, lugs, and webs all play a 
part in the problem. Casting and shrinkage strains occurring in the casting 
operation must be considered as well as the comparative die cost of the various 
possible designs. 

If a particular surface must be perfect and smooth it should always be so 
specified, as almost all castings have ejector pin marks made by the pins in ejecting 
the castings. The casting can usualh' be so placed in the die or the method of 
ejection so arranged that these marks will not show if proper information is re- 
ceived in the beginning. 




Milking machine part. Tin alloy. If not die-cast, this part would have to be made of tubing 
soldered together. The tubes would have to be machined, bent, and expanded for the hose 
connections. The cost would be many times that of the die-casting which is also more 

accurate and rigid. 



42 



Magneto breaker box. 




Magneto 
housing. 



Magnet c 
end plat 



GeJierat( 
end piec 



Tinier at 
rotor. 



Gcnerati 
dust 
cover o) 
oiler. 



.4!n niiniini and sine alloys. 
43 



Breaker box. 



When parts are to be assembled as many parts as possible should be combined 
in one piece. But it sometimes happens that a piece is so large or difficult that it 
will be cheaper to split it. When this is desirable it can always be done so that 
the part may be assembled in a simple and inexpensive manner. 

TJnrlpmitS Undercuts are the surfaces of a part which, when formed in 
the die, would prevent the ejection of the casting unless pro- 
vision is made in the die by means of moving parts to permit the part to pass out. 
The die opens at right angles to the parting line of the casting and it will readily 
be seen that to avoid undercuts the casting must gradually grow smaller above 
and below the parting line. It must always be remembered that every depression 
or irregular surface on a casting is not an undercut, as everything depends on how 
the part is placed in the die. In one position a part may have many undercuts and 
by being placed in another position these undercuts may disappear. 

The methods of forming undercuts in dies are 
limited only by the ingenuity of the designer. The 
usual practice is to construct moving cores or slides, 
but sometimes this cannot be done. In such cases 
collapsible cores or loose pieces may be used. Such 
construction should, of course, be avoided as much 
as possible, as it entails delicate and expensive die 
construction and delays production. Collapsible 
cores are also more or less inaccurate, and cannot 
be properly cooled. They are used to better advan- 
tage in other methods of manufacture. Sand cores 
also have been tried but without success. They are 
inaccurate and the sand gets into the dies and ma- 
chines, causing considerable trouble. The impact of 
the metal entering the casting breaks and chips them. 




A shows proper construc- 
tion for fastening lug. 

B forms an undercut, pre- 
venting withdrawal of the 
core. 



Fillets '^harp inside corners should be avoided, as they cause shrinkage cracks 
and also weaken the part. All such corners should be filleted. 

Metal at the great speed at which it enters the die does not flow as well 
around a sharp corner as when it is rounded. A sharp corner means a knife edge 
in the die and if the slightest surface crack occurs at this point the casting will 
break on slight pressure, in the same way that the cut of a diamond over glass 
causes the glass to crack. 

Fillets should be as large as the design and functions of the part permit. 
When another part fits the edge to be filleted it should be rounded to fit the fillet. 
A radius of ^{^o" or ^{;4" is sometimes enough for the purpose if more is not per- 
missible. 



Be3.cls I^eads are used for strength at the ends of tubes or thin surfaces or 
around slots or holes. They are also needed to help overcome crack- 
ing when the castings are made. 

44 




Parts of soda fountain pumps — tin alloy; 
Assembled pumps shown 
in the center. 



45 



"^^/'pko Reinforcement by webs is better than by thickening walls. Heavy 
walls, when other adjacent walls are light, are usually only "dead" 
metal, adding little strength in proportion to weight and expense. The chilled 
surface of a casting is stronger than the inner sections, which are also more or 
less porous. In considering the design of castings this must be borne in mind in 
addition to the other well known engineering advantages of web construction. 



Elbows or Curved Holes ^ ^'^'^^^ i" ^ h°l^ presents an undercut 

preventing a straight withdrawal of the 
core. It is usual, therefore, when withdrawing cores in a straight line to make 
the inside angle of the inner wall of the elbow sharp, as shown in the illustration. 

This is the simplest and quickest method of produc- 
ing such parts and therefore the least expensive. 

It frequently happens that this construction is 
objectionable and in such case we can produce almost 
any desired design. 

A tapering turn and also curved inside walls 
with no taper at the turn may be cast as shown in 
the illustrations. 

When the core can be withdrawn on an arc not 
exceeding about 100 degrees, no loose pieces in the 
die are needed. In such an event the end from 
which the curved core is withdrawn cannot have a 
straight portion at the opening. 



Elbow with rounded heiui (undercut). This is formed by a 
loose piece held on the ends of the cores in the position 
shown. After the cores are withdrawn this piece is knocked 
out of the casting-. 




Simple elbow with sharp 
angle bend. No undercut. 





The undercut section in the middle is formed by a loose core 
which is knocked out after the core in each end has been 
withdrawn. This construction requires a substantially in- 
creasing taper to permit ejection of the loose core. 




Curved core withdrawn on an arc. 



46 



!?S? 



^ 



^ ^ . 




Frame plates for moving picture machine. Zinc 
alloys. These plates must be held to extreme 
accuracy, as they are used to mount and assem- 
ble the mechanism of the machine. They illus- 
trate proper use of fillets and iveb construction. 



47 




Threads Outside or inside threads may be cast. Outside threads are 
usually cast by splitting the die lengthwise across the thread or 
forming it in the same manner on slides. A square thread cannot be cast in this 
way because it forms an undercut as it approaches the parting line, but it could be 
cast by inserting a bushing with an inside thread in the die and turning it off the 
casting. This is slow and troublesome work and should be avoided if possible. 

One or two turns of the thread should generally be omitted from the open 
end of a thread. If the thread extends all the way to the end it results in a 
feather edge on the part as well as in the die, which will easily break or wear and 
interfere with the use of the thread. 

Outside threads commonly have an angle of 29 degrees, 55 degrees, or 60 
degrees, and may be held accurate from plus or minus .001" to plus or minus 
.003", according to size. 

Inside threads are cast by turning out the threaded core, but small diameters 
and sometimes the larger sizes may be machined more cheaply, due to the time 
lost on the casting machine in doing this work. When a number of small holes 
are to be tapped it is totally impractical to attempt to cast them with the threads 
and the universal practice is to tap them. 

Threads should be made as coarse as possible as they are then less likely to 
chip in casting and are stronger and more accurate. 

In casting parts with pipe connections the better practice is to cast a hole 
and tap a female thread as shown in illustration B instead of casting a boss with 
an outside thread as shown in illustration A. The wedg- 
ing action of a pipe thread exerts a strain which has a 
tendency to break such bosses, and the design does not 
permit strengthening without shutting off the opening 
in the boss, (^n the other hand as much metal ns needed 
for strength can usually be added around an inside 
thread which, being larger in diameter than the pipe, is 
considerably stronger anyway. 

48 





lI'j'CH RULE 



Oears Gears operating at high speeds under loads subjecting them to heavy 
strain should not be die-cast. It is also not possible to die-cast gears 
in zinc and aluminum alloys with the same accuracy as they can be machined, and 
such gears are consequently not as quiet. Spur gears cannot be cast without taper 
on each tooth towards the parting line of the die. The few examples of die-cast 
gears made by us shown in the illustration will give an idea of the range of this 
work. 

EnPTavinP" Castings may be engraved in any manner desired but certain 
important considerations must be borne in mind. The cheap- 
est and simplest method is to engrave the die by sinking letters or designs into it. 
This results in raised engraving on the casting. 

If engraving is to be depressed into the casting as though it were directly 
engraved into it, the work in the die must be raised, which is sometimes an expen- 
sive and difficult operation, as it involves cutting away the entire surface around 
the engraving. 

When it is not desired that the letters project beyond the casting the engrav- 
ing may be raised but on a depressed mat. This is simple, as it merely involves 
inserting a plug in the die. 

When changes of engraving are desired, interchangeable plugs may be made. 
Engraving may be put on curved or flat surface but it must have plenty of taper 







Type-Wheel for CheckProtector. 
Zinc alloy. Letters in right end 
of part cast depressed to permit 
filling in with white enamel. 



49 




Drill Stands. 



to prevent chipping of the edges. For the same reason the engraving must be 
very carefully done and the letters polished. 

If engraving is to be put ort any part of a casting which rubs the die in 
ejecting it forms an undercut and must be made on a slide or a core, which has 
to be withdrawn before the casting leaves the die. 

C^learance for Tools ^" machining parts having threads or gears run- 
ning into a shoulder or flange it is generally 
necessary to allow for clearance for the cutting tool. In the design of die-cast- 
ings, however, it is permissible to extend such threads or gears up to the shoulder 
without any intervening recess or groove, as this construction is not needed in 
making the die. 



^ * 




Number lu/ieel for 
time flock, j" di- 
ameter. Tin alloy. 



50 



VI. Accuracy 



Accuracy in a die-casting depends first of all on the accuracy with which the 
die is made. The die is virtually a gauge which fixes the size of each part cast 
from it. 

The size and design of a part and the metal used also affect its accuracy. 
Small castings can be held closer than large ones. Long flat castings warp more. 
Castings having an odd and complicated design sometimes shrink irregularly. 
Most of the shrinkage takes place after the castings leave the die. 

In large castings the die temperature, if permitted to vary materially between 
operations, as well as the temperatures at which the metal is cast, will affect the 
accuracy of the part. 

Precision die-casting machines are particularly well adapted to meet these 
difficulties. They are so constructed that proper temperature regulation of dies, 
machine and metal is easy. The operation of the machine is regular and con- 
stant. The position of the dies on the machine, as well as our method of operat- 
ing and cooling them, all help to keep casting conditions uniform, which in turn 
afFects the flow and finish of the metal as well as the shrinkage. 

Accuracy is of course also affected by cleaning operations and removal of 
gates. This work is therefore given close supervision in our shops. 

In specifying dimensions the finished or final sizes should be given and no 
allowance for shrinkage made, as this must be taken care of by us in the die. For 
those, however, who desire the information we give the shrinkage of our alloys. 



Lead and tin alloys about .002" per inch 

Zinc alloys about .004" per inch 

Aluminum alloys about .007" per inch 




Number nvheels. 



51 



Exact tables on the accuracy to which die-castings may be held cannot be 
given as it varies with each part. An idea may be formed from the following 
table which, however, for some parts may be too close and for others too liberal: 

In dimensions of O-l" l"to2" 2" to 4" 4" to 8" 8" or over 

Lead and tin allovs ±.001" ±.0015" ±.002" ±.003" ±.0035" 

Zinc alloys '. ± .0015" ± .002" ± .003" ± .0035" ± .004" 

Aluminum alloys ± .002" ± .003" ± .004" ± .005" ± .006" 

On particular sizes our engineering department's opinion should be secured 
and permissible limits agreed upon. 

Dimensions across the parting line of dies are more difficult to hold to close 
limits, because it is almost impossible to keep the die surfaces absolutely clean. 
We use compressed air under high pressure to clean all particles of dirt and metal 
from the die surfaces. 

The pressure used in casting also has a tendency to force the dies apart. This 
is more in evidence in large castings made under high pressures and cannot always 
be entirely prevented. 

In most cases, when necessary, we are able to guarantee work as close as 
± .002" to =b .004" across the parting line, according to the casting. 

To a more limited extent there is a certain amount of inaccuracy in those 
parts of castings which are formed by slides or moving parts in the dies, as dirt or 
particles of metal sometimes prevent the slides or cores from going completely 
home. There must also be a certain amount of freedom in such parts to permit 
easy operation. By close and careful workmanship, great accuracy may neverthe- 
less be maintained. 

Holes in which a very close fit is needed, i. e., less than a variation of .001" 
should be reamed and stock allowed in the casting for this process. We suggest : 

Holes yi" or less in diameter allow about .004" for reaming 
Holes li" to 1" in diameter allow about .006" for reaming 
Holes 1" or over in diameter allow about .010" for reaming 

When parts are to be ground, about .005" should be allowed, and when ma- 
chining is to be done, about .010". 

All holes or walls from which slides or cores must be horizontally withdrawn 
or which in ejecting rub die surfaces must be tapered, except in the soft tin and 
lead alloys. Without taper the die will rub the casting, causing it to chip and 
crack. When the parts leave the die they are so hot that they are still very frail, 
and slight pressure will fracture them. 

As much taper as possible (from .005" to .010" or more per inch) should be 
allowed as it reduces cost by increasing production and also strengthens the parts. 

When taper is objectionable the following table will show the smallest 
amount of draft with which practical results in average cases can be obtained : 

Hard tin and lead alloys 00025" per inch 

Zinc alloys 0025" per inch 

Aluminum alloys 003" per inch 

52 



Extreme accuracy in ever^' dimension is expensive because it greatly increases 
the time necessarily spent on die work. Close or particular sizes should therefore 
be specified and the accuracy to which they must be held agreed upon. When 
sizes are specified in fractions instead of decimals it is generally understood that 
more liberal limits are permissible. 

When parts are to fit others not made by us, the best practice is to furnish 
gauges, to which we will work. In such cases the kind of fit desired should be 
specified, i, e., whether snug, loose, or tight. 

When the dies are first made for parts that must fit others, we always work 
safely, making the fit loose, and after the first samples are made it becomes a 
simple matter to determine just how much metal to add to make the fit right. If 
the fit should be too tight new cores or parts in the die would have to be made, as 
the change involves adding metal to the die surface. 



Pulley ^vheels, 
zinc alloys. Five 
speed pulley in 
center. 




53 





.K^_i/ 



Aluminum magneto housing. Cast iron pole pieces 
cast in sides and laminated inserts cast in top and bottom. 



VII. Inserts 



In many cases, when the metal of which a part is to be die-cast is not suitable 
for certain parts or functions of the die-casting, an insert of some other more 
suitable metal or material may be placed in the die and the metal cast around it. 

Inserts generally increase the cost of castings as the time needed to handle 
them in the dies delays production. On the other hand they may make otherwise 
difficult pieces simpler and less troublesome to cast or may replace more expensive 
metals with cheaper ones, in which case the cost is reduced. 

Much also depends on the design of the part and the location of the insert, 
which may be so inaccessible in the die that it would be cheaper to drive or screw 
it into the part after it is made. 

Subject to rare exceptions, inserts should not be used to strengthen or re- 
enforce a casting by imbedding them entirely in the metal, as for instance is the 
practice in concrete construction. The surface of an insert does not adhere to the 
casting by alloying with the surrounding metal. It merely lays in the metal just 
as if it w^ere driven in cold. It would fall out if enough of the casting is removed 
to release its grip on the insert. Consequently the insert really makes the sur- 
rounding walls of a given section so much smaller and thinner, so that when 
strains and stresses are applied to them they are more likely to break or crack and 
tear away, exposing the insert. If the strains could be taken up by the insert 
without first passing through the surrounding walls the case might of course be 
different. 

Inserts must be large enough to be handled easily by the machine operator, 
who wears one and sometimes two gloves on each hand for protection from the 
heat. 

54 



That part of an insert which is imbedded in the casting should be knurled, 
roughened or so shaped that the metal in shrinking will hold it in place without 
depending in shrinkage pressure alone. 

Some part of an insert, sufficient to hold it in the die, must always be ex- 
posed; it could not "float" in the die, as then its location could not be controlled. 

Inserts should be accurate. Pins or studs fitting into a hole in the dies must 
fit properly. If they are rough and have burr^^they will wear away the die. If 
they are too large they will not fit. If too small, the die will not grip them 
properly and the inrushing metal will shift them. Frequently the inserts are so 
placed that the dies close upon them. In such cases, if they are too large they may 
seriously injure the die. 

It is advisable to avoid the use of inserts so placed that the metal will shrink 
away from them instead of to them, as for instance an insert forming the outer 
wall of a casting. 

Hardened or tempered inserts may be used without injury except in alumi- 
num die-castings. 

Inserts are not furnished by us because it would be impractical to install the 
wide variety of equipment needed to make the many different kinds of inserts 
used. They can undoubtedly be bought to better advantage from specialists if 
not made bv the customer. 



H 




D 



A Zinc tone arm, brass tube insert. 

B Aluminum magneto housing. Iron 

pole piece cast in. 
C Aluminum magneto core. Steel shaft 

and laminated inserts. 
D Check protector lever. Cross hatch, 

hardened steel perforator inserted. 

55 



E Moving picture machine part. Brass 

insert. 
F Gasoline economizer. Copper wire 

mesh insert. 
G Aluminum optical instrument parts. 

Threaded brass tube insert. 
H Zinc ratchet, steel shaft. 




Bushing formed from sheet. 



f\ 



\ 



o 



')iilWiJlJllBlWhiw0JJ^ 



Cast Bushing drilled for 
anchorage. 



Bearings and Bushings When a special bearing surface to provide 

for excessive wear is needed, bronze, steel, 
or graphite bushings may be cast in. 

If thin stock is used it is preferable to cut grooves in the bushings instead of 
knurling them, as knurling will spread them, causing them to enlarge. 

Oil holes in inner bushing should be drilled 
afterwards when possible, because of the difficulty 
of lining up core pins to fit such holes. The delay 
in production usually amounts to more than the cost 
of drilling. 

When bushings must line up with other parts 
in an assembly or must fit perfectly the better prac- 
tice is to allow .005" or .010" for reaming after the 
castings are made. 

A cheap and effective bushing may be formed 
up out of sheet brass or steel in one or two opera- 
tions. It should be left with the seam open as 
shown. 

Bushings must be accurate and smooth, to fit the dies and prevent excessive 
wear. 

Studs or Pins ^ sufficient part of such inserts must always be left ex- 
posed (extending from the casting) to permit the die to 
properly hold it in place. When the design does not permit this it is sometimes 
necessary to cut ofif the insert after the casting is made. 

The portion of the insert imbedded in the casting, commencing about jV " O'' 
more from the surface of the casting, should be knurled, flattened, grooved or 
squeezed to provide a better grip. 

Provision must always be made in the casting to firmly anchor the insert, 
having in mind the strength and characteristics of the particular die-cast metal 
used. 

When studs are cast into a wall the opposite side of which is to be polished 
or finished, a better appearance will be presented if the base of the stud is pointed 
to prevent its showing through on the surface, as suggested in the illustration 
below on the extreme right. 




Methods of anchoring pins or studs. 



56 



Plat Snrinp'S Except in aluminum, springs may be inserted without draw- 
ing the temper. Springs are usually anchored by punching 
holes in them. In some cases eyelets are punched into the holes of the springs to 
give a better hold. 

Springs .003" to .005" thick should not be over ^" wide as otherwise the 
metal in shrinking will "pucker" them. 

Til hi nO" Tubing may be used when the design calls for long thin walls w^hich 
cannot be cast. It is sometimes used for its strength, or to afford a 
passage for corrosive liquids. It may be bent in any shape and used as an oil pas- 
sage, following an irregular line through the casting. It is advisable to extend 
tubing into which cores cannot be fitted bayond the surface of the casting to pre- 
vent the tube from being filled with metal. Such tubes must also usually be 
braced with pins or cores in the die which are withdrawn when the casting is 
made but leave holes in the casting up to the outside surface of the tube. 

Plates and. PlinchinP'S ^Vhen flat plates are inserted and exposed on 

one face only, it is necessary to hold them in 
the die with cores or pins running to the face imbedded in the casting. These 
cores when withdrawn leave holes in the casting. Discs should be countersunk 
and perforated to permit the metal to grip them. 



Sheet meral insert, shown 
imbedded in section of cast- 
ing. Frequently used to 
form bearing for breaker 
box on magnetos. 




57 



VIII. Die-Casting Processes 

The origin of modern die-casting practice may be traced to the development 
of the type-casting machine.' Such machines were built in this country as far 
back as 1838 and were used for lead and tin alloys only. 

The pioneers were Bruce, J. J. Sturgis, W. P. Bair, C. & B. H. Dusenberg 
and others. In 1885 Mergenthaler brought out his linotype machine and it was 
the ease and precision with which this machine cast type that suggested the use of 
a similar principle in casting machine parts out of zinc alloys, which have fusing 
points ranging only about 200° F. higher than type metals and are much stronger 
and harder. 

It is almost a fundamental principle that accurate castings of high fusing 
metals cannot be made in commercial quantities without the application of pres- 
sure and the use of metal dies. Steel, iron and bronzes have for many years been 
cast in metal molds by gravity but not accurately and with sharp outlines, and the 
castings are limited to simple solid pieces. 

C^lothiaS Process The distinction should here be pointed out between 

the die-casting process and the American application 
of the French "Clothias" process, in which various non-metallic molding com- 
positions are used. These molds are finer and more substantial than sand and 
may be used from two to upwards of twenty times, depending on the part cast 
and the accuracy required. The molds are made from patterns and the metal 
poured by gravity. Each time the mold is used it becomes less accurate and no 
moving parts or "permanent" cores may be used. The "Clothias" process, al- 
though it has been claimed to produce die-castings by at least one manufacturer 
using it, is merely a refinement of the sand casting process and does not offer the 
accuracy or range of the die-casting process. 

Note. — Illustrations and descriptions of various metliods of die-casting 
are given in Reference Booiis publislied by "Machinery" (The 
Industrial Press, New York City), No. 108 "Die-Casting Ma- 
chines" and No. 109" Die-Casting Dies, Machines, Methods". 
See also "Van Wagner Mfg. Co.'s Die-Casting Practice", 1 and 2, 
published in the January and February, 1913, numbers of "Ma- 
chinery" and articles there referred to. 

Compression Chamber ^^^ die-casting processes, as the term is gen- 

erally understood today, employ a compres- 
sion chamber in some form, in which the metal is subjected to pressure while 
liquid, and from which it is forced into metallic dies. This chamber may be 
large enough to hold sufficient metal for only one casting or for a great number. 
Various methods of applying pressure have been used. Type casting ma- 
chines employ a piston traveling in a cylinder and this method has proven satisfac- 
tory in casting metals melting at 950° F. or less. Compressed air is widely used 
and is generally adopted when the fusing point is above 950 degrees, as under 
such conditions a plunger cannot be operated. In modern dental casting ma- 

58 



chines explosive gases are used and in some European processes explosives in the 
form of cartridges furnish the necessary pressure. Centrifugal force has been 
employed especially in dental work by spinning the metal chamber and die and 
then opening a valve, which permits the metal to rush into the mold. This 
process is slow and can be used only for small parts. It produces very solid 
castings but is impractical for general commercial application. Iron piston rings 
are being successfully cast in this manner. In this instance a compression cham- 
ber is not used, but the metal is poured into the center of a rapidly revolving die 
which is made up of steel discs. 

Although the plunger construction has proven serviceable it involves many 
difficulties, especially when zinc alloys are used. If the plunger is fitted close to 
the cylinder to secure good compression it frequently sticks, due to unequal ex- 
pansion and warping. Sticking is also caused by dross which becomes wedged 
between the plunger and cylinder, forming a sandy mass of oxides and metals 
which alloy with the iron, sometimes practically brazing the plunger to the cylin- 
der. When this occurs the pmnp must be removed and the plunger drilled or cut 
out. If on the other hand the plunger is loose, the necessary pressure cannot be 
obtained. When plungers are well fitted they may sometimes, with care, be 
operated as long as a month before they become worn too much for use. Plung- 
ers cannot be left at rest in a cylinder for any length of tune and must always 




Parts for vending machines. Zinc and aluininuin alloys. 



59 



be removed when the machine is not in use, as otherwise they will "stick" or solder 
to the cylinder, necessitating their being machined out. 

Compressed air is objectionable for use with metals that have a tendency to 
dross excessively, and it is difficult to keep tight joints at the temperatures and 
pressures needed for die-casting. These objections can be minimized by ingenuity 
in design, and at temperatures over 950° F. compressed air is thoroughly practical 
and efficient if properly applied. 

The pressure chamber sometimes consists of the entire pot of metal which is 
covered with an air tight cover and heated with gas or oil fuels, or it may be 
immersed in an open pot in the form of a pump or a "goose neck" having suitable 
openings below and above the metal. The pressure chamber is connected directly 
to the die or die carriage by means of a nozzle. Pressure chambers must be made 
from metal as no other known substance will carry the required pressures at the 
casting temperatures of the metals die-cast. Cast iron is almost universally used 
for this purpose; malleable iron is also used. Steel is attacked more readily by 
molten metals and has not been as satisfactor\ . 



F)lP Position """^^ ^'^ ^^"^ ^^ '" ^"-'* P'^^'t'"" with relation to the pot. On 
some machines the pot is raised and the die operated under- 
neath it. This requires the use of a valve to shut off the metal when the die is 
removed. In other cases the die is on the side of the pot, which also requires a 
valve to retain the metal in the pot. When the die is placed above the level of 
the pot no valve is needed, but then the metal must be forced upward into the 
die, which by some authorities is considered inadvisable. It is no doubt better to 
let the gravity assist instead of hinder the casting operation, but the use of valves 
involves so many troubles and objectionable features that working against gravity 
is by far the lesser of the two evils. 

Except for use at comparatively low temperatures no valve has yet been 
made which will operate satisfactorily in molten metal, due to the wear and the 
action of the metal in eating away the surfaces of the valve. 



nriltinP" Pots ^" some machines the metal chamber tilts. Either the en- 
tire pot of metal is tilted or a smaller chamber immersed 
in the pot. In one case the pot is mounted on brackets with the die above it; 
when a casting is made, pot and die are turned upside down and then the pressure 
is applied by compressed air in the pot. It is claimed that by this process the 
metal enters the dies by gravity and that the pressure in the pot is only applied 
when the die and gate are filled with metal, the pressure merely densifying the 
casting. The fallacy of this is apparent to anyone who has tried to pour metal 
into a die by gravity. The metal chills almost instantly and before it has passed 
out of the gate in many cases. The moment the metal chills it stops the flow and 
no amount of pressure will fill the mold. To make a die-casting the pressure 
must be applied to the metal before it enters the die and the finish and accuracy of 

60 



the casting will be largely dependent on the speed with which the metal enters the 
die. If the speed of the inrushing metal permits it to fill the die faster than the 
die can chill the outer layers of a body of metal of that shape, a good casting can 
be made ; otherwise the casting will show heavy ridges, run marks, etc., and the 
impression in the die will not completely fill up. The revolving of a large pot 
and heavy die is slow and the metal in the pot is pretty well shaken up, atomizing 
and breaking it up, the very thing which is disclaimed for the process. It would 
seem that a simpler and more direct method of forcing the metal into the dies 
could be used, with resultant increase in production and less wear and tear on 
machinery. 

Much has been said of the tilting pot or compression chamber, but it is doubt- 
ful if it has any advantages. A tilting compression chamber immersed in ^ pot 
can easily be filled but it has no other advantage and has the disadvantage of not 
being rigid. Due to its motion tight air connections cannot be maintained. Air 
leakage seriously reduces pressures, which of course affects the quality of the 
castings. 

" ^jp-U Pots*' ^ machine widely used has the pot containing molten 
metal above the die and the pressure is applied on the 
entire pot. This requires the use of a valve, which is a rod passing through the 
top of the pot into an opening in the bottom. After a little use the valve wears 
and leaks and then it frequently happens that all the metal runs out of the pot. 
To avoid this, long bearing surfaces are provided and a certain amount of depend- 
ence is placed on the fact that the metal will chill at the gate and act as a plug to 
prevent further leakage. This plug of chilled metal, however, enters every cast- 
ing and in some cases prevents the obtaining of best results ; as a matter of fact, 




Bracket, 
zinc alloy. 



Auto ^cashing 

de-vice, 
aluTnuium. 



Bearing cap R. R. s^vitrli 

Liberty Motor, signal part, 

aluminum. zinc alloy. 



61 



moving a large body of metal suddenly downward much faster than it can be car- 
ried by gravity has no advantage over moving a small amount of metal suddenly 
upward, but on the contrary, the smaller body can be moved upward in a die- 
casting machine more easily and more rapidly, and in doing so all valves under 
liquid metal are avoided. 

Vacuum Process ^" some processes a vacuum is used to exhaust the air 

from the die cavity just before casting, and it has been 
asserted that by this means denser castings can be produced. The best results 
obtained have never justified the claims made for the vacuum processes. 

The process of die-casting is such in its very nature that absolutely solid 
castings cannot be produced by it. All molten metals contain gases which collect 
in the metal and form "blow holes". These gases, when metals are cast in sand, 
are allowed to escape through the pores of the sand while the castings slowly cool. 
No gases can escape through the walls of a metal die and there is no chance for 
escape anyway, as the castings chill instantly. We overcome these conditions 
largely by using high grade pure metals and alloys that give off as little gas as 
possible under closely regulated temperatures. 

The metal enters the die at such velocity that it splashes or sprays in some 
cases, permitting gases to escape into the mold and trapping them and air again 
almost instantly in chilling. This can be regulated by the size, location or direc- 
tion of the gate. 

In some castings the flow of the metal has a tendency to collect bubbles at 
certain points. The same result may be noticed when water is forced raj idly 
around a sharp corner, A bubble will cling to the corner no matter how great 
the speed of the water. This is caused by the change in direction of force, the 
heaviest particles of matter being carried the farthest away from the corner and 
the lightest, being most easily changed in direction, passing nearest the corner. In 
addition a partial vacuum is formed by the tendency of all the particles of matter 
to continue in the same direction, and into this vacuum the air and gases are 
drawn from the water. The same thing is noticed when an object is moved 
rapidly through water; a vacuum is formed directly behind the moving object, 
into which a certain amount of air and gases normally present are drawn. 

It is the same condition which is frequently responsible for "blow holes" at 
certain points in die-castings, and it is apparent that the difficulty is not overcome 
by casting into a partial vacuum. It is possible, however, in most cases to over- 
come conditions of this kind by changing the size and direction of the gate or its 
location. 

If the die is properly vented and gated, the pressure of the inrushing metal 
will force out all the air instantly and a vacuum is unnecessary. Even if a little 
air should stay behind it would not be the cause of porosity in a casting. Castings 
are made at pressures ranging from about 20 to 70 atmospheres. In other words, 
if a casting were made in an hermetically sealed die, only about one- 
twentieth or one-seventieth of the volume of the cavity would be air. Under 

62 



ordinary conditions it would be impossible to make a casting in a die from which 
less than about 95% of the air has escaped. Therefore the ordinary casting made 
with the usual pressure would only contain one-fourth of 1% to one-fourteenth 
of 1 % of the original air of the die cavity by volume. This would not be suffi- 
cient to affect the strength of a casting perceptibly as it would be distributed 
through the casting. 

If the vacuum is not shut off the moment the metal enters the die, in some 
cases the sucking action of the vacuum has a tendency to draw or suck the metal 
to the air vents, sealing them and thereby producing a condition much worse than 
if no vacuum were used. To overcome this, diaphragms have been used to bal- 
ance the vacuum in the die against a vacuum in the metal chamber, but this only 
prevents the sucking of the metal into the die before pressure is applied to the 
compression chamber. The best evidence after all is the result, and in this no 
vacuum process has shown any improvement in product over the approved and 
successful processes in which no vacuum is employed. It must also be borne in 
mind that conditions about a casting machine are such that a high vacuum can not 
be maintained due to the heat, chips and fins, dust and dirt, etc., constantly pres- 
ent. 

Die-castings can no doubt be made in countless ways, and the many processes 
in use have all produced a commercial product in quantities. But it has been 
done in most cases at an unnecessarily high cost in time, labor and difficulties en- 
countered, and naturally these factors have had a negative influence on the quality 
of the product. 

T^ip C^arriaP'eS ^^^ "^'^^ ^^'^ usually mounted on a carriage on which they 
are opened and closed. The carriage is usually in the form 
of two plates to which the dies are bolted and the plates slide on two or four bars. 
This carriage is attached to the frame of the machine either rigidly or on a hinge 
in such a manner that the dies may be swung away from the nozzle through which 
the metal passes, to permit ejection of castings and cleaning of the die and nozzle. 

The general practice is to open and close the dies by hand by means of tog- 
gles and to hold the die carriage to the nozzle of the machine by means of clamps, 
which are also operated by hand. The pumping in plunger machines is also gen- 
erally a hand operation. Hand operated die carriages cannot be made strong and 
substantial enough except for very light castings to give the best results, due to the 
weight of large dies and the great pressure of the metal entering the dies. Great 
strength and endurance is required and it is therefore very difficult to keep high 
class labor at this work, except at prohibitive wages. Low grade labor cannot be 
used to produce good work and causes much loss by the production of cracked and 
defective castings. 

The difficulty in applying power to die-casting machine operation has been 
the varied character of the dies which had to be used and the necessity of holding 
the dies closed under high pressure. The mechanical action of a press of any 
character, for instance, would be entirely unsuitable. It has been difficult to 
63 



adjust casting pressures and speeds mechanically to the requirements of different 
dies and it seemed at one time almost impossible to construct a die carriage which 
could be operated mechanically and which would not involve too much time and 
trouble to adjust it to any die that might in the usual course be used. Power 
driven and automatic machines for use in connection with tin and lead alloys and 
for small and comparatively simple parts such as, for instance, type, counter 
wheels, and small parts used in connection therewith, have been in use for some 
time but are not practical for general use with high fusing metals. 

Feedinp" Metal into Dies There are two methods of feeding the 

metal into the dies. One between the 
die surfaces, in which case the nozzle through which the metal enters the dies is 
at the parting line of the dies ; the other through the lower die-block opposite the 
ejector side, in which case the nozzle through which the metal enters the die is at 
right angles to the parting line. In the latter case a sprue cutter or gate former 
is needed. 

The gate former is usually a tapered bushing attached to a handle which is 
placed into the die for each operation. It is placed between the die and the nozzle 
of the casting machine. After the casting is made the gate former is turned 
usually on a cam so as to lift it out of the die. At the same time it breaks off the 
sprue or gate to permit ejection through the die block. 

The sprue cutter is simply a rod or bar which passes through the die into 
the opening through w^hich the metal enters the die, called the gate. When the 
casting is made the sprue cutter is raised free of the gate and the instant the die 
impression has been filled the sprue cutter is pushed into the gate, closing it and 
cutting off the flow of metal. This facilitates the removal of the sprue from the 
die and prevents the metal from running out of the die before it sets should the 
pressure be released. It also makes it possible to gate through a hole in a casting 
or into its side without leaving a gate or sprue on the casting as it comes out of 
the die. 

A certain amount of skill and experience are needed to operate sprue cutters, 
as they must be operated at the instant the die is filled. A fraction of a second 
early or late may spoil the casting for obvious reasons. 

Sprue cutters wear more than cores and are therefore not so accurate when 
they are used to form any surface of a casting. 

Inasmuch as a sprue cutter cuts off the flow of the metal, it cuts off the pres- 
sure, and the moment the metal contracts it is no longer under pressure. The 
beneficial effect of the pressure then is lost on the unsolidified parts of the casting 
and most important of all, it is not possible to feed in metal to make up for the 
contraction of the casting. This tends to make the center of a heavy part porous 
and spong}' and also affects its accuracy, as the shrinkage will not be so great 
when additional metal is fed into the casting under pressure to make up for its 
contraction in cooling. Lighter parts, however, do not show any appreciable 
difference when made with or without a sprue cutter. 

64 




Mo-x'i/ig belt 
in Trimming 
Room, Fay- 
ette-x'i/le plant. 



Precision Die-Ca.StinP" Precision die-casting machines are the result 

of scientific analysis of the causes of defective 
riOCcSScS work and an ingenious application of ma- 

chine power to replace all hand labor in ma- 
chine operation. 

We use both hand operated and power driven machines, as we have found 
that one type of machines cannot be used with best results for all work. The 
hand operated machines are used for very light work and their ingenious design 
makes the labor light and operation fast. Some castings have been made on these 
machines at the rate of 450 per hour, which means the average operation of the 
machine seven and one-half times per minute. 

The power machines are not automatic in the sense that they may be run 
without the direction of an operator, but they are in the sense that they automati- 
cally perform the various operations required to produce a die-casting by the 
operation of a control lever. Their advantage over other machines lies not only 
in the elimination of heavy labor but in the accuracy with which they may be 
adjusted and controlled, and the greater speed and power they develop. Each 
die requires different handling to produce the best results. The proper speed and 
pressure for the metal in entering the dies is easily determined and when once 
fixed is constantly maintained by simple adjustments on the machine. 

Each machine is equipped with a pyrometer which records the metal tempera- 
ture, which is maintained within a limit of 20 degrees. The proper temperature 
65 



of dies is likewise determined and maintained by thermostatic water temperature 
control. No clamps or toggles are used to operate dies, and the die operating 
mechanism is very heavy and substantial, remaining rigid and firm under any pres- 
sure. This prevents inaccuracy and cracking of castings due to shifting of dies. 

We have profited by our own mistakes and have tried to learn as much as 
possible from the mistakes of others. No known improvement in modern die- 
casting practice has been overlooked by our engineers. Every detail of our equip- 
ment has been developed with a view to the production of castings of uniform 
quality above all other considerations ; cost and speed of production being consid- 
ered next. In practice we have found by close comparison that in most cases the 
method which produced the best castings was in the long run also the speediest and 
lowest in point of cost. 




Special presses for 
removing gates 
and fins. Trimming 
Room, Fayetteville 
Planf. 



66 




Carburetor parts. Aluminum and zinc alloys. 



IX. Machining Die-Castings 

Making allowance for the peculiarities of the particular metals used, die- 
castings are machined the same as other castings. We have found that speeds, 
feeds and cutting steels cannot be applied by rule, but it requires judgment and a 
certain amount of experimenting to determine the best practice in each case. 

Only high speed steels should be used for cutting tools. Machine or tool 
steels do not hold their edge. 

For zinc alloys cutting speeds should be from 10% to 20% faster than usual, 
and for aluminum from 20% to 40% faster; and feeds about 25% slower. 

Tools must be kept sharp. This is one of the most important things to keep 
in mind. Dull tools will tear the metal and forge or spread it. They will cause 
comparatively thin walls to crack, due to the wedging action of a dull tool. 

Taps and reamers should have large flutes to give plenty of room for chips 
to escape. 

Tools should have at least 5 degrees clearance. This amount will avoid 
chatter, but if fast work is required the clearance should be increased. Soft alumi- 
num die-castings require more than 5 degrees clearance. When an end mill is 
used better results will be secured if every other tooth is cut back to a sharper 
angle; that is, for instance, alternating between an angle of 70° and 40°. 

Tap holes should be from .003" to .005" in diameter larger than for ordinary 
work, due to the rolling or spreading action of the tap, which will bring the 
thread up to the right size. 

In tapping or reaming parts having thin walls it is best to make fixtures 
which will grip the castings in such a way that the walls will be supported against 
the spreading action of the tools. 

Zinc metals do not require cutting lubricants although it is sometimes better 
to use them. For aluminum alloys cutting lubricants should be used. For zinc 
67 



alloys any good lubricant that will wash out chips and keep the tool cool will do, 
such as soda water, soap water, turpentine and kerosene in equal proportions, lard 
oil, etc. For aluminum we recommend a mixture of one part lard oil to three 
parts benzine. There are a number of good cutting compounds for aluminum on 
the market. 

In grinding or filing die-castings the wheels or files can be kept from becom- 
ing filled or clogged with metal to a certain extent by applying tallow or chalk or 
both. A file known as the "Vixen" gives better results than ordinary files and 
grinding wheels are sometimes kept well oiled with ordinary lubricating oil to 
prevent the pores from filling with metal. 





i 



Aluminum '"''Strut Sockets'' for aeroplanes. 



68 



X. Electro Plating Die-Castings 

PolishinP" ^V^hen a polished surface is required buffing is essential. For 
very fine work the surface is first polished with about 150 emery, 
which must be applied with a mixture of parafine and beef suet, prepared with 
carbolic acid to kill any germs. Dry emery will tear the surface and imbed itself 
in the castings, so that it will be impossible to secure a proper finish. The surface 
only should be touched and care should be taken not to go below the "skin" of the 
casting. The castings are then cut down with Tripoli compound or similar 
material. After this, color with White Acme Compound. In handling fine 
work, gloves dipped in whiting should be used. 

Long tubular pieces should be polished lengthwise and not crosswise to avoid 
a wavy surface. 

Except for the very finest work, the emery polishing operation may be 
omitted. 

The castings should not be allowed to get so hot that they cannot be held in 
the hand, as it will cause them to crack and will injure the surface of the castings. 



Clca.ninP' ^^ '" '^^^ processes, the surface of the castings must be freed from 
grease, oxides and all foreign substances. 

Dirt and polishing material are sometimes first removed with gasoline or 
benzine. 

The castings are then immersed in a hot solution at about 150° F. If 
necessary the cleaner may contain about one-half pound of caustic soda to the 
gallon, but should never be so hot or strong that it attacks the metal to any appre- 
ciable extent, and the dip should be for a few seconds only. There are several 
less harmful cleaning solutions on the market containing mild alkalis which may 
be secured from any well stocked plating supply house. A good cleaner is made 
up of one pound of soda ash and about one-quarter ounce cyanide of potassium to 
the gallon of water. 

The caustic cleaners re-act with the grease usually present on all castings, 
forming a soap, which goes into solution. They also re-act with the zinc in zinc 
base alloys forming zinc oxide and hydrogen. When the metal is placed in the hot 
bath, the pores open and permit some of the caustic solution to enter. If there- 
after the casting is at once plunged into a cold bath, the pores will suddenly close 
and trap the cleaning solution, which in time, will act on the zinc and generate 
hydrogen gas. If the casting is plated in this condition the gas in attempting to 
escape raises the layer of plating, forming blisters which eventually causes the 
plate to peel off. 

It is therefore advisable to wash out all salts before they are trapped in the 
pores of the metal by immersing in two changes of clean water of the same tem- 
perature as the cleaning bath. 

Castings which have been corroded by contact with moisture or liquids form- 
ing oxide of zinc on the surface may first be cleaned by dipping for a few seconds 
69 



in a solution of four parts of water to one of hydrochloric acid, which will dis- 
solve the oxide. This solution should of course be cold and the parts should im- 
mediately be washed in water of the same temperature before passing through 
other cleaning operations and brushed to color. This operation is not used when 
the castings are first polished, as surface corrosion would be removed sufficiently 
by that operation. 

Another method of cleaning is with what is known as an electric cleaning 
bath. The solution usually contains various alkalies, as carbonate of soda, cyan- 
ide, etc. 

A formula strongly recommended is : 

Caustic soda Yi lb. 

Carbonate of soda Yi lb. 

Sodium cyanide Y2 lb. 

Water 1 gal. 

In the electric cleaner nascent hydrogen and sodium are liberated at the 
cathode. The hydrogen reduces the oxides and the sodium, re-acts with the water, 
forming caustic soda, which saponifies the grease on the cathode surfaces. For 
zinc castings the temperature of the bath should be about 150° F. and the E. M. 
F. about 6 volts with a high current density. 

After the castings have been washed thoroughly it is sometimes productive of 
better results to rub them with a paste of Vienna lime, using a soft bristle brush. 
They should then he thoroughly washed in cold water and they are then ready for 
the plating bath. 

PlatinP" Baths Next to magnesium and aluminum, zinc is the most elec- 
tro-positive of the common metals. When metallic zinc 
is immersed in an acid solution containing metals electro-negative to it, those 
metals are reduced to their metallic state in the form of fine particles, usually 
black in color and sometimes in a spongy mass. Nickel, cobalt, tin, copper, gold, 
and silver, the metals usually plated, are all electro-negative to zinc, and between 
them and zinc there is in consequence a high difference in potential. This differ- 
ence is smaller in an alkaline than in an acid bath. 

When for instance zinc castings are immersed in a nickel bath, a reaction 
instantly occurs before the electric current acts, whereby some nickel is deposited 
on the casting by "immersion" in the form of a black finely divided non-adherent 
metallic powder. Such deposit when coated with grey nickel, as sometimes hap- 
pens after a substantial black deposit, causes the plating to become loose and peel. 

This black deposit usually shows in the form of streaks at such points on the 
casting which have not been subjected to the action of the current. 

Attempts to overcome this by introducing various salts intended to reduce 
the potential between the zinc and nickel have not proven satisfactory. Magne- 
sium sulphate has been recommended for the purpose. 

The addition of sodium nitrate to the bath is sometimes recommended, al- 
though the function of this salt is not to reduce the difference in potential, but to 
retard the chemical deposition of the black powder on the zinc, which it does to a 

limited extent. 

70 



Another difficult}' sometimes arises in plating nickel on zinc, when the parts 
are irregular in shape, containing hollows or cavities. The current densities in 
the hollows are smaller than on the more exposed surfaces, giving the nickel a 
splendid opportunity' to deposit by immersion and cause black streaks. 

The theory has been advanced that the streaking is due to the decomposition 
of nickel sulphide in an alkaline bath and the generation of nickel sulphate 
(black). While this may be true in an alkiline bath, the streaking generally 
occurs in acid electrolytes, which are the base of most nickel baths. 

When streaking cannot be otherwise overcome, it may be avoided by flashing 
or striking the castings in a nickel or copper bath in which deposition by immer- 
sion cannot take place. Such a bath is usually an ordinary plating bath but with 
a high alkali content (caustic or cyanide) and a small metal content; It is oper- 
ated at a high voltage, giving the metal very little opportunity to deposit by im- 
mersion. Castings are kept in this bath for about 20 seconds. This operation is 
often performed in connection with an electric cleaning bath, in which case it must 
be maintained at low temperature, since deposition by immersion takes place 
rapidly in a hot solution. In this bath the cleaning and plating are simultaneous. 
It is a very satisfactory method of securing good adherent deposits, but involves 
the trouble and expense of an extra operation. 

In plating zinc as little free cyanide as possible should be used to avoid blis- 
tering. 

Nickel Ba.th ^" ^^^ cases the deposition should be started with an E. M. 
F. of about 5 or 6 volts and then reduced to about 2^ or 3 
volts. In doing this care must be taken that the initial voltage is not maintained 
long enough to burn the work. For direct nickel plating on zinc die-castings 
Hammond proposes the use of the following bath : 

Single nickel sulphate 34 oz. 

Nickel chloride 2 oz. 

Boric acid 4 oz. 

Sodium citrate 24 oz. 

Water 1 gal. 

The boric acid is an excellent substitute for the mineral acids on account of 
its weakness. The sodium citrate retards the deposition by immersion, although 
it does not alter the difference in potential between the metals. This bath should 
be kept at room temperature. 

For flat articles having no recess or hollows, the following bath wnll give 
satisfactory results : 

Double nickel salts 6 oz. 

Single nickel salts 3 oz. 

Nickel chloride 2 oz. 

Boric acid 1 oz. 

Water 1 gal. 

Voltage at start 6 volts and gradually reduce to about 3. Keep the bath 
slightly acid with boric acid. 
71 



Another bath proposed by Hammond for the same purpose is: 

Single nickel salts 16 oz. 

Nickel chloride 2 oz. 

Boric acid 4 oz. 

Water 1 gal. 

Another formula which will give good results is: 

Nickel sulphate 4 oz. 

Potassium citrate 23 oz. 

Ammonium chloride 4 oz. 

Water 1 gal. 

The usual high voltage at about 5 or 6 to start, reducing at once to about 3. 
The bath should be kept as nearly neutral as possible to avoid deposition by im- 
mersion resulting in black spots or streaks. Caustic potash may be added for 
this purpose. 

All nickel baths should be as near the neutral point as possible, i. e., the}' 
should not be strongly acid or alkaline. If the solution becomes too alkaline, 
boric acid should be added until it becomes slightly acid. If the solution becomes 
too acid sufficient caustic potash to overcome this should be added. Over acidity 
will cause black spots or streaks, the result of deposition by immersion. 

Brass Ba.th l^'''iss is deposited in the same manner as copper, with the addi- 
tion of zinc salts. The ratio of zinc to copper should not be in 
the proportions used in making alloys, but rather in the proportion of the chemical 
equivalents of the two metals, i. e., 63^2 parts of copper and 3212 parts of zinc. 
The color may be deepened or made lighter by reducing or increasing the zinc 
content. 

A good formula is : 

Copper cyanide 4 oz. 

Zinc cyanide 4 oz. 

Soda or potassium Q. S. 

Water 1 gal. 

Slight excess above that necessary to dissolve zinc 
and copper. 

Anodes of rolled brass should be used with an anode surface always in excess 
of the area to be plated. E. M. F. about 5 volts, best worked in room tempera- 
ture. There should always be sufficient free cyanide in the bath to keep the 
anodes clean and free from slime, for which purpose a very small excess is needed, 
which should be kept as low as possible. 

Temperature: Either room temperature or higher. 

Another bath recommended is : 

Sodium carbonate 4 oz. 

Sodium bisulphate 3 oz. 

Copper cyanide 2 oz. 

Zinc cyanide 2 oz. 

Potassium or sodium Q. S. to clean and a slight 

excess. 
Water 1 gal. 

CoDDCr Ba.th Castings are seldom copper plated for finish but it is usually 

done as a base for another deposit or to protect castings 

from corrosion, which may be done by a copper "strike" or "starting" bath pre- 

72 



viously described. For direct copper plating an alkaline bath is best. A good 
formula is: 

Copper cyanide 4 oz. 

Sodium or potassium Q. S. with slight excess. 

Water 1 gal. 

Potassium or sodium carbonate is usually recommended in such baths but it 
is unnecessary because some of the excess sodium cyanide, being exposed to the 
surface, is converted to carbonate. Too much of an excess of sodium cyanide is 
harmful and it is therefore better to have a small excess and replenish the bath 
occasionally. 

Best results are obtained with cast anodes; they should be cleaned and 
scrubbed occasionally to remove the slime, vv^hich materially weakens the conduc- 
tivity of the bath. Keep bath at room temperature; E. M. F. 2^2 to 3 volts, 
with initial of about 5. 

After the castings have been "struck" in copper, other finishes may be applied 
according to general plating practice. 

X*in Bath "^"^^ castings should receive the same treatment for cleaning as for 
nickel plating. Copper strike for 15 or 20 seconds, which may be 
done in an electric cleaning bath. Wash in cold water and then place in pyro- 
phosphate bath as follows : 

Sodium pyrophosphate 10 oz. 

Stannous chloride (fused) 1 oz. 

Water 6 gal. 

The bath should be maintained at room temperature; E. M. F. about 3;!/ 
volts. The tin salts are difficult to dissolve in the pyro-solution and therefore the 
best method is to enclose them in a muslin bag which should be hung just below 
the surface and moved to and fro frequently. 

Cast tin anodes of the highest quality should be used, but the tin content will 
not remain constant as the anode dissolves at a lower rate than deposition takes 
place. Tin should therefore be added periodically by adding solution or hanging 
a bag of stannous chloride in the bath. An objection which has been made to this 
bath is its low tin content. 

A bath highly recommended by Mather & Cockrum (trans) Electro. Chem. 

Soc. 29 (1916) is: 

Stannous oxalate 5% 

Ammonium oxalate 6% 

Oxalic acid 1^% 

Peptone i% 

Balance water. 

Reduced to the English system the formula will be : 

Stannous oxalate 7 oz. 

Ammonium oxalate 8 oz. 

Oxalic acid 2 oz. 

Peptone Ys oz. 

Water 1 gal. 

This bath is said to give firm, thick and smooth deposits and has the advan- 
tage of a higher tin content. Stannous oxalate must nevertheless be added per- 
iodically to maintain the tin content of the electrolyte at the proper proportion. 

73 



Silvfr RatH The casting should be cleaned in the usual waj' and then 
flashed in a silver striking bath as follows: 

Silver cyanide ^ oz. 

Sodium cyanide 8 oz. 

Water 1 gal. 

The castings should be left in this solution 15 or 20 seconds at a voltage of 
5 or 6, after which they may be placed in the silver bath. 

A preliminary plating or coating is needed to prevent deposition by immer- 
sion, which will cause peeling. 

In place of the silver strike a copper or nickel strike may be used but the 
copper is not advisable when a very thin silver coating is to be given, as the color 
will show through. The castings are then, after washing, dipped in a mercury 
bath as follow^s : 

Red oxide of mercury ^ oz. 

Potassium or sodium cyanide 8 oz. 

Water 3 qts. 

The immersion should last about 5 or 6 seconds, in which time a thin film 
of mercury will be formed which will make the silver adhere better. When it is 
desired to reduce the expense of plating as much as possible, the striking bath may 
be omitted and the articles merely quickened in the mercury dip before silver plat- 
ing. They may be immersed in the silver bath after the dip without rinsing in 
water. 

The silver bath is : 

Cyanide of silver 22 oz. 

Sodium cyanide Q. S. 

Water 1 gal. 

Q. S. Sufficient to convert the silver nitrate to the double cyanide (solution 
of the cyanide) and an excess of about one (1) ounce of sodium or potassium 
cyanide. This excess is needed to convert the silver cyanide which forms at the 
anode into the double cyanide. If this is not affected, the anode will become sur- 
rounded with an insoluble crust of silver cyanide, which increases the resistance to 
the current. 

Sufficient cyanide should be constantly added to keep the anode free from 
slime and dirt. 

Use rolled silver anodes. Initial voltage of about 6, which should be re- 
duced to 2y2 to 3. Room temperature. 

Gold Ba.th """'^^ castings should first be well coated with copper or brass 
and a good lustre maintained on the surface. It would be very 
wasteful to deposit gold directly on zinc as a good deal of the deposit would be 
absorbed in the castings. The copper or brass finish furnishes a background for 
the gold, making it possible to secure good results with a comparatively light de- 
posit. 

The ordinary bath is : 

Gold cyanide 1 oz. 

Water 1 gal. 

Sodium or potassium cyanide Q. S. 

74 



Q. S. Sufficient to dissolve the gold cyanide and clear the solution. The 
cyanide should be kept low, just enough to keep the anodes clear. Too much 
cjanide will produce a pale, dirty color. Use anodes of fine gold rolled thin to 
keep the gold content in the bath down. A thin sheet of carbon may also be used. 
Maintain bath a room temperature, but when desired to keep the gold content 
down as little as one-third ounce can be used and the temperature kept at 150° F. 
High temperature is not advisable. If the color becomes 3'ellowish and "brassy" 
add more gold to the solution by adding gold cyanide dissolved with sodium or 
potassium cyanide ; E. M. F. about 3 volts. 

The following formula is also recommended : 

Phosphate of soda 8 oz. 

Sulphide of soda ij oz. 

Sodium cyanide 6 penny wt. 

Chloride of gold 6 pennywt. 

Water 1 gal. 

E. M. F. about 2y2 volts at about 160 degrees Fahrenheit. 

The casting should be protected with the usual "banana oil" lacquers for the 
silver and gold finishes when possible. The base of these lacquers is usually gun 
cotton dissolved in amyl acetate. A good coach varnish may also be used, thinned 
with turpentine or benzine. 

Aluminum Polishinp* Aluminum will take a very high polish. This 

is especially true of alimiinum-copper alloys, 
which have a very much harder surface than pure aluminum. 

The parts are sometimes first dipped in a dilute solution of caustic potash and 
then thoroughly rinsed and dried. 

The polish should be free from grit and alkali. Nos. 120-150 emery is used 
applied on a rag or felt wheel with glue. The parts are then buffed with pumice 
stone and oil or rouge. 

The polish will be retained as well as on silver but must of course be kept 
bright and clean and given the same attention as other metals. 

PicklinP" Aluminum ^^ remove particles of fat, oxide and other 

substances a hot 10% solution of cooking 
soda saturated with common salt is sometimes used and parts dipped for 15 to 20 
seconds, then brushed and dipped again for 20 seconds, then washed well in run- 
ning water and dried. This will give a color resembling matted silver. 

KleCtrO-PlatinP" '^^^ electro plating of aluminum is attendant with 

. , . more or less difficulty, due to its being highly electro- 

i~\.l UllllUUm positive to all the baser metals (including zinc) except 

magnesium, and deposition by immersion therefore 
takes place in the same manner as described with zinc castings. (See p. 70). 

Another difficulty is that aluminum becomes coated with a film of oxide in- 
stantly on exposure to oxygen, which prevents the deposit from adhering to the 
surface of the parts. 
75 



These difficulties are somewhat eliminated when copper-aluminum alloys are 
used. Metals containing 8% to 18% of copper, balance aluminum, can be given 
a good adherent deposit. 

The following method of plating aluminum is recommended in the Brass 
JVorld oi May, 1907: 

Clean the article from grease and dirt in the usual way and then dip in a 5% 
pickle of hydrofluoric acid, then "quicken" in a mercury bath for a few seconds 
and again place in the hydrofluoric pickle imtil it commences to bubble. It is 
now ready to be copper plated or silver plated before it is nickeled. The copper 
bath should be about 150° F. 

A new method of nickel plating is the subject of a patent described in a 
French scientific journal. It is claimed the deposit is firm and adherent, practi- 
cally forming an alio}' of aluminum and nickel. It will stand hammering and 
can (like sheet metals) be bent without cracking the plating, according to the 
authority. 

The parts are thoroughly cleaned first in a bath of boiling potash to remove 
grease and are then scrubbed with milk of lime. This is followed by soaking in a 
bath of 2% potassium cyanide for several minutes. Next a bath is made of 500 
parts of hydrochloric acid, 500 parts water and 1 part iron. The part is kept in 
this dip until it takes on an appearance of what the inventor calls "metalling 
watering". After each of these operations the part is carefully washed in water. 

The metal is now ready for the nickel bath, proposed as follows: 

Water 1 gal. 

Nichel chloride 7 oz. 

Boric acid 3 oz. 

An E. M. F. of 2>2 volts is used. The plate takes a high lustre on polish- 
ing. 

Note. — See "Nickel Plating Cast or Sheet Aluminum," Metal Industry 
for January, 1919, page 25. 




Aluminum "Jane" 
for aerial bombs. 



76 



XI. Lacquers, Enamels and Chemical 

Finishes 

All metal parts before the application of any finish must be thoroughly 
cleaned and all foreign matter removed from the surface, to permit the coating to 
come in direct contact with the metal. The usual methods of cleaning die-cast- 
ings for electro-plating baths may be followed (see p. 69) or the castings may be 
washed in hot soapy solutions. Gold-Dust, Oakite or any mild cleanser may be 
used, after which the parts should be thoroughly rinsed in water of the same tem- 
perature as the cleaning bath, then washed in water at room temperature, and 
then thoroughly dried if enamels, lacquers or paints are to be applied. All fin- 
ishes which are apt to discolor or corrode or which are easily brushed or worn ofi 
should be protected with a good metal lacquer or varnish. A good lacquer com- 
monly used is made by dissolving about 1 oz. of cellulose nitrate in about a quart 
of amylacitate and thinning the mixture with grain alcohol mixed with ether. 
Some add fusil oil to the amylacitate. 

As a rule lacquers can be bought to better advantage prepared according to 
requirements from responsible manufacturers. 

Cold LaCQlierS and After cleaning, the parts may be sprayed with 

El an air brush or dipped with lacquers and enam- 

namels , . • , , . k k i ^ r u i 

els, which need not be baked. L-old enamels 
usually have a celluloid base. Best results are 
obtained if a filler is first applied. The filler gives the work a richer tone 
and also is more adherent, thereby making the enamel stick better. The filler 
usuall}' takes about half an hour to dry and the enamel, which is generally first 
thinned down, may be applied. This will dry in about one-half to two hours, 
according to the material used. Materials for this finish may be secured from 
several of the larger paint manufacturers and a list of names will gladly be fur- 
nished on request. 

Ba.k.cd Ena.mcl I^'^'^^d enamel is applied to die-castings in the same man- 
ner as to other metals. In all cases except aluminum, 
the castings must not be heated to more than about 250° degrees F. Enamels 
which will bake satisfactorily at this temperature may be secured from standard 
paint concerns. 

IVleta.1 Finishes A^^^^' being cleaned the parts may be coated with alumi- 
num, bronze, or gold lacquers. Metallic powders are 
used for this purpose, giving any desired finish. The powders are mixed with a 
suitable carrying liquid, either a good light coach varnish or a metal lacquer. 

The coach varnish is preferable for interior work. Before using it should 
be thinned with turpentine or benzine. For exterior work lacquer is more last- 
ing and will not crack or peel. 
77 



Rlark Kim'sll Aluminum, zinc and other alloys may be given a 

finish similar to gun metal by dipping in the foUow- 
Antimony Dip ing solution, after being cleansed: 

Hydrochloric acid 12% 

Antimonv chloride 1 to 2% 

Water ' 86 to 87% 

The parts should be immersed till well coated with a deep black powder and 
then thoroughly rinsed in clean water and dried, preferably with hot air. The 
black powder should then be brushed or very lightly buffed off. 

The parts should then be coated with coach varnish or transparent lacquer, as 
otherwise the finish will come off in time. 



Coloring Aluminum According to a patented process (U. S. patent 

No. 1023291, issued to S. Axelrod) aluminum 
may be durably finished in colors ranging from steel grey to brown and finally to 
black, depending on the temperature at which the work is done. The surface of 
the aluminum is treated with a solution of cobaltous nitrate maintained either 
neutral or slightly alkaline. The parts are then heated by muffle or blow pipe. 
A low temperature wmII color it steel grey and as the heat is increased the color 
deepens to brown and finally to black. It is claimed the black will not wear off 
by friction. 

Aluminum may also be coated a brown color of different shades by dipping 
in ammonium solutions which attack the surface, forming a coating more resistant 
than the natural metal. This coating, although attacked rapidly by concentrated 
acid or alkaline solutions, resists corrosion from air and moisture as well as from 
dilute mineral and organic acids. 

Black Oxidizinp" ^ *^^^P black finish may be secured by first copper 

plating the parts in the usual way and then dipping 
them in a solution of liver of sulphur. If desired, portions of the parts may then 
be buffed, exposing the copper background. This finish should be protected with 
a good coat of lacquer or varnish. 

Note. — A very comprehensive article on chemical finishes appears in 
American Machinist, issues of April 27 and May 18, 1911. 



78 



XII. Soldering Die-Castings 

7\r\C AlloVS ^^"^ "^ ^^^ chief reasons difficulty has sometimes been encoun- 
tered in soldering zinc die-castings is the formation of a fine 
coating of aluminum oxide on the die-cast surface. The heat conductivit.v of 
zinc is high, causing the solder to chill when applied and thereby preventing it 
from alloying with the zinc. It is also necessary not to heat the metal over about 
275° F. 

Any low fusing solder may be used (see Solder Alloys, p. 87). A good 
solder of almost the same hardness and color of the zinc alloys is composed of : 

Cadmium 50% 

Tin 30% 

Zinc 20% 

If cadmium is not desired the following formula may be used: 

Zinc 15% 

Tin 841% 

Aluminum s% 

A flux should be used. We suggest a solution of zinc chloride (about 20%) 
acidified with a few drops of hydrochloric (muriatic) acid, sufficient to keep the 
salt in solution. The acid if not removed will discolor and corrode the metal 
around the soldering joint. If this is objectionable, powdered rosin may be used 
as a "flux" but it is a little more difficult to handle. To overcome this the rosin 
may be dissolved in alcohol. 

The solder should be well rubbed into the casting before it chills to permit it 
to alloy with the zinc. If possible the parts to be soldered should be rubbed 
against each other and heated sufficiently to keep the solder liquid while this is 
done. 

The castings after being fluxed are sometimes dipped in molten solder which 
may be kept in a small pot over a low flame. Care should be taken not to over- 
heat the solder, which causes a volatilization of the metals. If the solder becomes 
coated with a film of oxide, clean it with a pinch of sal-ammoniac. 

After the parts are dipped they are assembled under the heat of a small torch. 

If notwithstanding the instructions here given peculiar conditions existing in 
any particular case cause trouble, it may prove helpful to use a mercuric flux, 
made up of a saturated solution of mercuric chloride, to which may be added 5 
drops hydrochloric acid to every ounce of solution. The mercury acts as a binder 
making the solder adhere to the part. 

SolderinP" Aluminum Low temperature solders should not be used 

as aluminum will not alloy with solders at 
low heats. Ordinary solders alloy with copper at about 450° F., which is in- 
creased to about 650° F. in the case of aluminum. 

It is difficult to maintain the proper soldering temperature in working alumi- 
num because it is such an excellent conductor of heat. The aluminum by con- 
veying the heat rapidly away from the point to be soldered reduces the tempera- 
ture at that point below that needed to properly alloy the solder with the part. 
79 



It is frequently said that aluminum is difficult to solder because it has a 
"greasy" surface. This is a misconception, but the chief trouble is nevertheless 
to the same effect in prmciple. Aluminum on being exposed to the air, instantly 
becomes coated with a fine invisible film of oxide, which prevents the solder from 
coming in direct contact with the metal. In order to secure a good joint, it is 
therefore necessary to secure a clean surface by removing this coating. 

When metals other than aluminum are to be soldered, it is easy to do this 
with fluxes or soldering salts, but no satisfactory chemical method of removing 
the oxide from the surface of aluminum has been found. 

No flux should therefore be used except such cleaning fluids as may be needed 
to clean the surface of dirt and grease. This only applies to the tinning of the 
aluminum surface, but after it has been tinned the usual fluxes should be used. 

Aluminum should be soldered by heating it to about 650° F. and rubbing 
the solder into the surface of the metal with a stick of solder, or with a blunt in- 
strument or brass wire brush. In this manner the oxide film will be mixed into 
the solder and the solder permitted to come in direct contact with the part before 
any air can touch the aluminum surface. The solder must be rubbed in thor- 
oughly and care taken that during the operation it remains perfectly liquid. After 
the surface is "tinned" it may be soldered to other parts in the usual way. 

The best method of applying the heat is by blast lamp or blow pipe. A sol- 
dering iron is not as satisfactory. The durability of the joint will depend upon 
the care and thoroughness with which the solder is "rubbed in". 

The chief ingredients in aluminum solders are tin and zinc. Other metals 
in small proportions are frequently recommended in addition, but their utility has 
not been demonstrated. Among these are cadmium, bismuth, lead, copper and 
nickel. 

The most widely used and no doubt an excellent formula is that patented in 

1892 by Joseph Richards and generally known as Richards' solder. It contains 

Phosphor tin 1 part 

Tin 29 parts 

Zinc 11 parts 

This metal is tough and very nearly the color of aluminum. If phosphor tin 
is not desired or available one part of aluminum may be substituted. 

It is not practical to make solder flow into an aluminum joint. The solder 
must be put where it is wanted by "tinning" the parts first. After being prepared 
the parts are held together and heated sufficiently to make the solder fluid and 
then they may be chilled by plunging in water. Care must be taken to permit 
the joint to set and it should not be moved while the solder is fluid. 

A soldered aluminum joint will not hold under water or in moist air and all 
such joints should be painted, varnished or coated to protect them from corrosion. 

As has been previously pointed out, metals corrode and disintegrate rapidly 
in the presence of moisture when in contact with other metals electro-negative to 
them. Tin and zinc are electro-negative to aluminum, but no better elements 
for soldering aluminum have been found. 

Note. — An instructive article, "Solders for Aluminum," will be found in 
the Metal Industry for November, 1918. Copy of this article can 
be secured from the Bureau of Standards, Washington, D. C. 

80 



WeldinP" Aluminum ^^^ different commercial processes of welding 

may with skill and experience be applied to 
aluminum die-castings in many cases. A very interesting article to those wishing 
more detailed information, by Paul D. Merica, appears in the September, 1918, 
issue of the Metal Record and Electroplater, under the title "Aluminum and Its 
Light Alloys." The same article is published by the Bureau of Standards, Wash- 
ington, D. C. (Circulars 76 and 78), and may be had on application. 

In general, soldering is preferable to welding except where special strength 
in the joint is required or where the parts will be exposed to moisture or water and 
can not be satisfactorily coated or painted. As previously explained, the electro- 
negative metals in the solders tend to cause disintegration in the joint in the pres- 
ence of moisture, but as no metals electro-negative to aluminum need be used in 
welding, welded joints are more lasting under such conditions. 

Care must be used in preheating the parts for welding. Too much heat will 
permanently weaken and warp the metal and cause it to sweat. A good test may 
be made with sawdust, the danger point being reached when the sawdust begins 
to char quickly. At the right heat it will char slightly and slowly. 

Cements Metal cements may on occasion be used to advantage instead of 
the more troublesome and expensive process of soldering. When 
little or no strain is put on the joint make up a putty of glycerine and lead oxide. 
When greater strength is required, mix sodium silicate (water glass) with zinc 
oxide to the consistency of a putty. After application dry for about 24 hours and 
then heat to about 150° F. for a short while. 

A very complete article on plastic cements with formulas may be found in 
the Brass World and Platers Guide for May, 1917. 



Fire extinguisher part, 
Antimonial lead. 




i^ 



"*9l^ 



81 



TABLES 



PRECISION ALLOYS 

During a period of over eleven years we have made and thoroughly tried 
hundreds of white metal alloys and made accurate observation of their qualities 
when new and after service for extended periods. 

The formulas given below have survived a process of elimination which has 
been thorough and rigid. In strength and service they completely cover the usual 
requirements of die-cast parts of all kinds. In rare cases very special requirements 
may justify a modification and in such cases our laboratory will gladly make 
recommendations that will suit the purpose if it is possible to do so within the 
limitations of the die-casting process. 



Sym- 
bol 


Tin 


% 
Cop- 
per 


% 
Lead 


% 
Anti- 
mony 


% 
Alum- 
inum 


DESCRIPTION 


AC 10 




10 






90 


Used for mechanical parts of all kinds. Ten- 
sile strength between 18,000 and 21,000 lbs. 
to square inch. Less than half the weight of 
cast iron. Not harmful to foods. Resistent 
to corrosion and atmospheric conditions but 
becomes coated with film of oxide in presence 
of moisture similar to brass. (We reserve 
right to vary copper content 5% above or 2% 
below formula given according to casting re- 
quirements of part.) 


SNl 


84 
S3~~ 


7 




9 




Highest grade genuine babbitt for high 
speeds and heavy loads. 


SN2 


5 




12 




Used for de'cicate and very accurate parts. 
Tensile strength comparatively low. Non- 
corrosive and not harmful to foods. Not 
affected by atmospheric conditions. 


SN3 


82 


6 


2 


10 




Higheslt grade babbitt for high speeds and 
medium loads. 


SN4 


81 


4 




15 




Same as SN 2 but harder. 


SN5 


61 


3 


25 


11 




An excellent babbitt for use in place of SN 3 
at lower cost. 


PBl 






87 


13 




Standard low cost anti-friction metal for 
light loads and medium speeds. Also used 
for mechanical parts not requiring strength. 
Harmful to food. Not corrosive. 


PB2 


15 




75 


10 




A good general purpose low cost babbitt. 
Tougher and stronger than PB-1. 


PBS 


10 


i 


82 


7h 




Same as PB-2 but slightly lower in cost. 


PB4 


5 




80 


15 




.\ serviceable babbitt similar to Magnolia 
Metal. 


ZNl 


6 


3 


' 


Zinc 
90 


X 

2 


Used for mechanical parts. Tensile strength 
12,000 to 16,000 lbs. Weight about same as 
cast iron. Softer than cast iron. Should be 
protected from moisture by a coating or plat- 
ing. Harmful to foods. Soluble in alkalis 
and mineral acids. Non-magnetic. Should not 
be subjected to more than 275° F. 


ZN2 


14 3 


i 


82 


a 

2 


Same as ZN 1 but softer and slightly more 
expensive. Frequently used for more fragile 
or difficult parts. 



83 



USEFUL INFORMATION 

To convert degrees Fahrenheit (F.) into Centigrade (C.) subtract 32, mul- 
tiply the remainder by 5 and divide by 9. To turn Centigrade into Fahrenheit, 
multiply the number of degrees by 9, divide by 5 and add 32. 

In the Reauner scale used in France 5° C. equal 4° R. 

33000 
One H. P. expressed in heat units = -^^ — = 42.416 heat units per min- 

ute. A British Thermal Unit (B. T. U.) is the heat required to raise the 
temperature of 1 lb. of water at or near 39° F. one degree F. One B. T, U. r= 
778 ft. lbs. One lb. of fuel per H. P. = 1,980,000 ft. lbs. per lb. of fuel or 
2,545 heat units per lb of fuel. 

Circumference of circle := diameter X 3.1416 

Diameter of circle := circumference X 0.3183 

Area of circle ^ square of diameter X 0.7854 

Length of arc ^ number of degrees X diameter X 0.008727 

To find the area of a triangle, multiply the base by one-half the perpendicu- 
lar height. 

To find the area of a trapezoid, add the two parallel sides together and mul- 
tiply the sum by half the perpendicular distance betw^een them. 

To find the area of a regular octagon, multiply the square of the diameter of 
the inscribed circle by the decimal .828. 

To find the area of a regular hexagon, multiply the square of the diameter 
of the inscribed circle by the decimal .866. 

A gallon of water (U. S. Stand.) weighs 8g lbs. and contains 231 cu. in. 

A cu. ft. of water contains 7.48052 U. S. gal., weighs 62.47 lbs. at 32° F. 

To find the pressure in lbs. per square inch of a column of water, multiply 
the height in feet by .434. 

Atmospheric air pressure at sea level is 14.7 lbs. per square inch. 

Specific gravity ^ weight of a body compared with the weight of an equal 
bulk of water. 

To find specific gravity. Divide the weight in air by the difference between 
the weight in air and submerged in water. 

GAUGES FOR VARIOUS MATERIALS* 

The gauges by which various metals are ordered and sold are not standardized and one metal 
may be ordered in a variety of gauges. It is safest in ordering to always specify the gauge, but a 
still better way and one which is gradually gaining ground, is ordering by decimal parts of an inch. 
The following table gives the gauges which are most usually used for a variety of materials, but, 
as before stated, the gauge shouM be specified in ordering. 

Material Gauge Material Gauge 

Steel Tubing U. S. S. Sheet Iron U. S. S. 

Seamless Brass Tubing Stubs Sheet Aluminum B. & S. 

Seamless Copper Tubing Stubs Sheet Steel U. S. S. 

Steel Wire U. S. S. Manganese Bronze Sheets B. & S. 

Brass Wire Stubs Brass Sheets B. & S. 

Copper Wire B. & S. Copper Sheetsi Stubs 

Iron Wire U. S. S. Steel Rods U. S. S. 



Tin Plate2. 



1 Copper sheets are also gauged by the weight in ounces per square foot and in the heavier 
sheets in pounds per sheet 30 x 60 inches. 

2 Tin plate is gauged by the weight of a basic box which contains 112 sheets each 14x20 
inches. This rule holds up to 100 lb. basis. The terms IC, IX, 2X, 3X, etc., are used for the 
heavier gauges, these terms designating plates weighting a certain number of pounds per basis box. 



*Data furnished by U. T. Hungerford Brass & Copper Co., J. M. & L. A. Osborn Co., Carter, 
D'onlevy & Co., and others. 

84 



JSB3 

qoui 'bs J3d 
■q^lSuaaiS 

3IISU3X 



ui 'bs jad 'sqi 

ill X;pi}SB[g[ 

JO HnpoM 



ssaupjBjj 



o oo 
o oo 
ooo 



rt VO <N t 



oo 

oo 
oo 
o'o 
oo 
o \o 



or^ o o o ^H 



}00} 

oiqno asd 
:>qSi3M 'sqq 



qaui 

oiqnD J3d 

jqSpM -sqq 



XjiABao 
oifpadg 



O O vo On oo <^ •-' "O o 

\o CO r^T-«.-iLni— tfoco 

.-I "D- ,-1 in Tl- f^ ^o "^ 1/-1 



OOnVOO CNt^ 000^-^c^fM^t^'-'a^»0^10^^rcOO 

u-iC^iooo Tj-o ^c^^cT^-T^lnlo^ooOLna^poTt•oo'M 

ir^Tf(M.-H n-l^ <X> rf u-j xn r^ '■O ■^ -^ '^ m rr> ^ ^ 



vor^T-<f*^ 00 On o or^r^ -^in Ti- Tf -^ oir) r^ on 

ooior>v'^ oo o CN o r^ ^ f-H o m ro fo o »-H 00 r^ 

^HTtONO vo^H ONOOO^HtxroOO'^OOVOONOONOO^ 



t^ CM 00 O "^ On 00 00 •-< 00 ^ On CM r^ r^ '-^ '-' ro 00 00 00 r-i 



. OS Tj-io c^r^ 



1 = ^^ OH 
X;iAi;Dnpuo3 



in t^ O u^ 00 ^O ^O 

O^OOOn VO '^ 00 
CM* cm' ' pO on ^] lO 



— CO O Tt 

00 ^ r^i ^' r^ 00 ^* fv^ 00 



001 = ov 

X;iAi;onp 
U03 l^Wjaqx 






3 l"]o<I 



pqiuXs 



O 1^ ,-. 



OOVO'Mt^O*i-Oi^]^u~iOLO^'-'^1-' 



'^rn<^"^0\'i-^OOroiOr^LnCMi-HOO 

I CNi U-) \o '-' i-H r-^ C] u-j "Tj- T^ t:j- rvi o\ t^ 



t^ irj O CM O O a\ CM Oin T m PO O "^ t 
IT) lo CM'=t'TlO'OC^]0\OOOO^^ro( 
'O ON ^d\OOOCMron-OOOmOCN]i--'» 



IvOOONt^-^OOl 

On ro cm O on t^ NtJ 










— 3 «J C 

"oH ox 0.2 2 ? 1^ 






;^^-- n! 3^;= 






53 S 

^ 3 



;HHH 



3^ 

Soy 



•*H O 

I' c 
-^ o 

"" o 

ojpq 

^^- 

-5 ij 






ft-" j: 



.g 






CT3 
















£2 > 


3 






^>.--3 






°-^ „ 










V 






'^2 








cj cd tu 


u 






see 


j: 








3 

a 






5^- 


T3 






Sgo 


rt 






ij'Z >■ 


-c 






j3 ca.t; 






















o 


X p li 


"' 






.y C bo 


o 




o 


•fi " o 






X 




ho 




3 
o 


;^ 






/3 ft 


O 




ft 


fcH-' 


^ 






c .^ 


rt 




^ 


rt o *^ 


>. 




~" 


cS 2 










> 


m 


cm' 




rt 








1) 

s 


B 


J3 
hn 


''go 






■" cu 










O 




■s 


S-=!a 




c 






Jl 


•^ 


c ; 


«,-^ >- 


c 


4_. 






o 


o 


^ 


-o^ 


ft 


>^ 




J3 -U 


M 


n! 





zr-B 


'ij 


3 


fe 


a « 


l; 






S 2-^ 




rt 


,_, 


■CB° 


u 


C 


o\ 


S"S 










H 
1 


C 


n) 


S rtjt: 


V 


C 


OJ 


nt 


o 


cS 
> 


^ 


rt n '- 






o -^ 




<u 




i^ -M 




o 




o 2 
PA'S 



85 



ELECTRO CHEMICAL SERIES 
("Weichmann" Notes on Chemistry) 



45 Silicon 

46 Titanium 

47 Columbian 

48 Tantalum 

49 Tellurium 

50 Antimony 

51 Carbon 

52 Boron 

53 Tungsten 

54 Molybdenu m 

55 Vanadium 

56 Chromium 

57 Arsenic 

58 Phosphorus 

59 Selenium 

60 Iodine 

61 Bromine 

62 Chlorine 

63 Fluorine 

64 Nitrogen 

65 Sulphur 

66 Oxygen 

to all the elements which 



METRIC CONVERSION TABLES 

Note. — Abbreviations: Millimeter, Mm. Centimeter, Cm. Meter, M. 
Kilometer, Km. Gramme, G. Kilogram, Kilo, or Kg. Metric 
Ton, M. T. Cubic Centimeter, C. C. Liter, L. 

1 Cm. = 10 Mm. 1 M. = 100 Cm. 1 Km. = 1000 M. 1 Kg. = 1000 G. 
1 Metric ton = 1000 Kg. 1 L. = 1000 C. C. 

A liter of water weighs a kilo and contains a cubic decimeter in volume. 

A U. S. gallon contains 231 cubic inches and weighs 8.345 lbs. of water at 
62° F. The English gallon correspondingly weighs 10.017 lbs. and contairrs 
277.27 cubic inches. An English gallon contains 4.54346 L. and is the equivalent 
of 1.20032 U. S. gallons. 

The following table gives only the denominations in practical and general 



1 Caesium 




23 


Nickel 


2 Rubidium 




24 


Cobalt 


3 Potassium 




25 


Thallium 


4 Sodium 




26 


Cadmium 


5 Lithium 




27 


Lead 


6 Barium 




28 


Germanium 


7 Strontium 




29 


Indium 


8 Calcium 




30 


Gallium 


9 Magnesium 




31 


Bismuth 


10 Beryllium 




32 


Uranium 


11 Ytterbium 




33 


Copper 


12 Erbium 




34 


Silver 


13 Scandium 




35 


Mercury 


14 Aluminum 




36 


Palladium 


15 Zirconium 




37 


Ruthenium 


16 Thorium 




38 


Rhodium 


17 Cerium 




39 


Platinum 


18 Didymium 




40 


Iridium 


19 Lanthanum 




41 


Osmium 


20 Manganese 




42 


Gold 


21 Zinc 




43 


Hvdrogen 


22 Iron 




44 


Tin 


In the above 


table 


each element is ele 


follow it. 









use: 

1 mm. 

1 cm. 

1 sq. cm. 

1 cub. cm. 

1 m. 

1 sq. m. 

1 cub. m. 

1 km. 

1 hectare 

1 L. 



1 g- 

1 kg. 
1 m. t. 



= .03937 in. 

= .3937 in. 

= .1550 sq. in. 

= .0610 cub. in. 

= 39.37 in. 

= 10.76 sq. ft. 

= 3 5.31 cub. ft. 

= .62137 miles 

= 2.471 acres 

^ 1 cub. decim. 

= .2642 U. S. gal. 

= 61.023 cub. in. 

= .03531 cub. ft. 

= 2.202 lbs. water 

= 33.84 fl. oz. 

^ 15.432 grains 

= .03527 oz. 

— 2.2046 lbs. 

— 1.102 tons (2000 lbs.) 
= .9842 tons (2240 lbs.) 



1 in. 




z^ 


25.4 mm. 






= 


2.54 cm. 


1 sq. in. 




^ 


6.452 sq. cm. 


1 cub. in. 




^ 


16.39 cub. cm. 


1 ft. 




=- 


.3048 m. 


1 sq. ft. 




^ 


.0929 sq. m. 


1 cub. ft. 




= 


.0283 cub. m. 


1 mile 




= 


1.6093 km. 


1 acre 




= 


.4047 hectares 


1 quart (liq 


uid) 


^ 


.9463 I. 


1 gal. U. S. 




^ 


3.785 1. 


1 fl. oz. 




:^ 


.02967 1. 


1 quart (dr\ 


•) 


^ 


1.101 1. 


1 bush. 




= 


35.24 I. 


1 oz. av'd.) 




= 


28.35 g. 


1 oz. (Tro\ 


) 


= 


31.10 g. 


1 lb. 




m: 


.4536 kg. 


1 ton (2240 


lbs.) 


= 


1.016 m. t. 


1 ton (2000 


lbs.) 


= 


.9072 m. t. 



86 



A FEW LOW FUSING ALLOYS AND SOLDERS 







% 


% 


% 


% 


Melting 


Point 






Lead 


Tin 


Bismuth 


Cadmium 


°C 


°F 


No. 


1 


96 


4 






292 


558 


No. 


2 


90 


10 






283 


541 


No. 


3 


83 


17 






266 


511 


No. 


4 


75 


25 






250 


482 


No. 


5 


67 


33 






227 


441 


No. 


6 


50 


50 






188 


370 



No. 7 

No. 8 

No. 9 

No. 10 

Isaac Newton's alloy. 

Rose's alloy 

Wod's alloy 

Lipowitz alloy 

D'Arcet's alloy 

Expanding alloy 



40 
33 
33 
10 
30 
28 
25 
27 
25 
67 



60 
67 
34 
40 
20 
22 
13 
13 
25 



33 

50 
50 
50 
50 
50 
50 



12 
10 



25 



168 

171 

140 

116 

100 

95 

60 

66 

93 

66 



334 
340 
284 
240 
212 
203 
140 
150 
200 
150 



NON-FERROUS METAL TUBING TOLERANCES 

Tubing can be furnished in copper, and the commercial alloys of copper and zinc, 
such as high brass, bronze, phosphor bronze, and tobin bronze. 

Composition. — As specified ot meet the requirements of use. 

Temper. — As specified in the order; may be hard, half hard or annealed. If an- 
nealed, the tubing may be soft, or light annealed. 

Size variation. — On inside and outside diameter and the thickness of the walls, as 
follows: 

Outside and Inside Dimensions 

Up to y2 in. inclusive 0.002 in. over or under 

Over J/j in. to and including 3^ in 0.0025 in. over or under 

Over 34 in. to and including 1 in 0.003 in. over or under 

Over 1 in. to and including IJ4 in 0.0035 in. over or under 

Over 1^ in. to and including IJo in 0.004 in. over or under 

Over l}/2 in. to and including 1^4 in 0.0045 in. over or under 

Over 1^ in. to and including 2 in 0.005 in. over or under 

Over 2 in 54 o^ 1 per cent, over or under 



No combination of variations on the same tube shall make the thickness of the wall 
vary from the nominal by more than the following amounts: 

Thickness of Wall 



Up to and including 1/64 in 0.001 



Over 1/64 
Over 1/32 
Over 1/16 
Over y^ 
Over 14 



n. to and 
n. to and 
n. to and 
n. to and 
n. to and 



ncluding 1/32 in 0.002 

ncluding 1/16 in 0.003 

ncluding Y^ in 0.005 

ncluding H in 0.008 

ncluding 5/16 in 0.0125 



Over 5/16 in. to and including -vy in 0.015 



n. over or under 
n. over or under 
n. over or under 
n. over or under 
n. over or under 
n. over or under 
n. over or under 



Special limits. — On all stock where the above commercial v-ariations are not per- 
missible limits shall be specified in the order. 

87 



CO-EFFICIENTS OF FRICTION 



The relative value of different materials of construction ascertained as the 
result of tests made by the National Brake & Clutch Company is tabulated as 

follows : 

Materials Co-efficient 
Metal and cork ) 

Leather and cork [■ on dry metal 0.35 

Fibre and cork 
Metal and cork 

Leather and cork }- on oily metal 0.32 

Fibre and cork J 

Fibre on dry metal 0.27 

Fibre on oily metal 0.10 

Leather on dry metal 0.23 

Leather on oily metal 0.15 

Charred leather on oily metal 0.08 

Metal on dry metal 0.15 

Metal on oilv metal 0.07 



The co-efficient will vary with the condition of the contacting surfaces. 
Smooth and unyielding surfaces offer less resistance than rough and yielding ones. 
In metal to metal contacts different metals are usually employed for the opposing 
surfaces, as bronze and steel in plate clutches and cast iron and steel in brakes of 
the shoe type. 

WEIGHTS AND MEASURES 



TROY WEIGHT 

20 grains = 1 pwt. 
20 pwts. ^ 1 ounce 
12 ounces = 1 pound. 

APOTHECARIES WEIGHT 
20 grains ^=. 1 scruple. 

3 scruples -■^=. 1 dram. 
8 drams =■ 1 ounce. 

12 ounces ^ 1 pound. 
The ounce and the pound in this are the 
same as in troy weight. 

AVOIRDUPOIS WEIGHT 

27gi grains ^ 1 dram. 
16 drams =■ 1 ounce. 
16 ounces ^ 1 pound. 
25 pounds = 1 quarter. 

4 quarters ^=- 1 cwt. 
2,000 lbs. — 1 short ton. 

DRV MEASURE 
2 pints :=: 1 quart. 
8 tjuarts ^ 1 peck. 
4 pecks ^ 1 bushel. 
36 bushels = chaldron. 

LIQUID MEASURE 

4 gills ^ 1 pint. 
2 pints = 1 quart. 
4 quarts = 1 gallon. 
31 >1 gallons = 1 barrel. 
2 barrels ^ 1 hogshead. 

TIME MEASURE 
60 seconds ^ 1 minute. 
60 minutes = 1 hour. 
24 hours == 1 day. 
7 days ^ 1 week. 
28, 29, 30 or 31 days ^ 1 calendar 
month (30 days = month in 
computing interest). 

365 days = 1 year. 

366 days ^ 1 leap year. 



CIRCULAR MEASURE 

60 seconds =■ 1 minute. 
60 minutes ;= 1 degree. 
30 degrees ^ 1 sign. 
90 degrees = 1 quadrant. 
4 quadrants := 12 signs, or 
degrees ^ 1 circle. 



360 



SURVEVOR'S MEASURE 
7.92 inches = 1 link. 
25 links = 1 rod. 
4 rods ^ 1 chain. 
10 sq. chains or 160 sq. rods ^ 

1 acre. 
640 acres = 1 square mile. 
36 sq. miles (6 miles square) ^ 

1 township. 

LONG MEASURE 
12 inches = 1 foot. 

3 feet ^ 1 yard. 

iV2 yards = 1 rod. 
40 rods = 1 furlong. 

8 furlongs ^ 1 sta. mile. 

3 miles ^ 1 league. 

SQUARE MEASURE 

144 sq. inches = 1 sq. ft. 
9 sq. ft. = 1 sq. yd. 
3054 sq- yds. = 1 sq. rod. 
40 sq. rods ^ 1 rood. 
4 roods ^ 1 acre. 
640 acres ^ 1 square mile. 

CUBIC MEASURE 
1,728 cubic in. = 1 cu. ft. 
21 cubic ft. = 1 cubic yd. 
128 cu. ft. =;: 1 cord (wood) 
40 cu. ft. = 1 ton (shpg). 
2,150.42 cu. in. = 1 standard bushel. 
231 cu. in. = 1 standard gallon. 
1 cu. ft. = about .8 of a bushel. 



DRILL SIZES FOR STANDARD THREADS 

Tap holes for die-castings should be .003" to .005" larger than the sizes given, due 
Aluminum and zinc alloys. 

These sizes give an allowance above the bottom of thread on sizes ^4 to 2 ; varying 
respectively as follows: for V" Threads, .010" to .055"; for U. S. S. and Whitworth 
threads, .005" to .027". 

These are found by adding to the size at bottom of thread ;4 of the pitch for "V" 
threads, and ^ of the pitch for U. S. S. and Whitworth, the pitch being equal to 1" — No. 
of threads per inch. 

In practice it is better to use a larger drill if the exact size called for cannot be had. 



Size 
Screw 


No. of 
Threads 


c 


HE OF Drill 


Size 

Screw 


IVn f^f 


s 


izE OF Drill 


u. s. s. 


"V" 


W. 


Threads 


U. S. s. 


"V 


W. 


% 


24 


.201 


.196 


.202 


\l 


9 


.808 


.790 


.810 


Va 


20 


.191 


.184 


.192 


1 


8 


.854 


8.32 


.856 


~h 


18 


.248 


.239 


.249 


\h 


8 


.917 


.894 


.919 


Vs 


16 


.302 


.293 


.303 


1>8 


7 


.957 


.932 


.950 


IV 


14 


.354 


.345 


.355 


1^4 


7 


1.082 


1.057 


1.085 


y2 


13 


.409 


.399 


.410 


IH 


6 


1.179 


1.144 


1.182 


^ 


12 


.402 


.391 


.403 


1/2 


6 


1.304 


1.269 


1.307 


-fir 


12 


.465 


.453 


.466 


15/i 


5/2 


1.412 


1.373 


1.416 


% 


11 


.518 


.506 


.520 


15/^ 


5 


1.390 


1.347 


1.394 


H 


11 


.581 


.568 


.583 


m 


5 


1.515 


1.473 


1.519 


Va 


10 


.632 


.618 


.634 


1% 


1 5 


1.640 


1.597 


1.644 


\l 


10 


.695 


.680 


.697 


m 


4 1/2 


1.614 


1.566 


1.619 


% 


9 


.745 


.728 


.747 


2 


4/ 


1.739 


1.691 


1.744 



DRILL SIZES FOR S. A. E. THREADS 





Size 


of Tap 


Size of Drill 


Va 


inch 


X 28 threads 


%o inch 


^\ 




x24 


1-/64 " 


H 




x24 


21/64 " 


t'b 




x20 


V% " 


V2 




x20 


t'b " 


IG 




xl8 


/ " 


5/8 




xl8 


i\ " 


1 1_ 




X 16 


«%4 •■ 


Va 




xl6 


4%4 " 


/s 




xl4 


2%2 " 


1 




xl4 


2%2 '■ 


1/8 




xl2 


1 1/64 " 


1/ 




X 12 


1 %4 " 


1/8 




xl2 


11 '/64 " 


1/ 




xl2 


12%4 " 



The above tap drills allow a thread within ^04 inch of full thread. 



89 



WIRE GAUGES 
Sizes in decimal parts of an inch 





American or 
Brown and 
Sharpe 


E 


0) 




."go 


= 




3 


.11 "^ 




c c 
•- a; 
3 o 

nl -a 


ij 3 
3 o • 


4= 3 -^ 
O L. c 


3 

o 

O 0, 

d "kT 


0000 


.46 


.454 


1.512 


.3938 


40.94 




0000 


000 


.40964 


.425 


1.412 


.3625 


34.73 




000 


00 


.3648 


.38 


1.265 


.3310 


29.04 




00 





.32486 


.34 


1.132 


.3065 


27.66 







1 


.2893 


.3 


1.000 


.2830 


21.23 


.227 


1 


2 


.25763 


.284 


.946 


.2625 


18.34 


.219 


2 


3 


.22942 


.259 


.863 


.2437 


15.78 


.212 


3 


4 


.20431 


.238 


.793 


.2253 


13.39 


.207 


4 


5 


.18194 


.22 


.733 


.2070 


11.35 


-204 


5 


6 


.16202 


.203 


.676 


.1920 


9.73 


.201 


6 


7 


.14428 


.18 


.600 


.1770 


8.03 


.199 


7 


8 


.12849 


.165 


.550 


.1620 


6.96 


.197 


8 


9 


.11443 


.148 


.493 


.1483 


5.08 


.194 


9 


10 


.10189 


.134 


.446 


.1350 


4.83 


.191 


10 


11 


.090742 


.12 


.400 


.1205 


3.82 


.188 


11 


12 


.080808 


.109 


.363 


.1055 


2.92 


.185 


12 


13 


.071961 


.095 


.316 


.0915 


2.24 


.182 


13 


14 


.064084 


.083 


.276 


.0800 


1.69 


.180 


14 


15 


.057068 


.072 


.240 


.0720 


1.37 


.178 


15 


16 


.05082 


.065 


.217 


.0625 


1.05 


.175 


16 


17 


.045257 


.058 


.193 


.0540 


.77 


.172 


17 


18 


.040303 


.049 


.165 


.0475 


.58 


.168 


18 


19 


.03589 


.042 


.140 


.0410 


.45 


.164 


19 


20 


.031961 


.035 


.117 


.0348 


.32 


.161 


20 


21 


.028462 


.032 


.107 


.03175 


.27 


.157 


21 


22 


.025347 


.028 


.093 


.0286 


.21 


.155 


22 


23 


.022571 


.025 


.083 


.0258 


.175 


.153 


23 


24 


.0201 


.022 


.073 


.0230 


.140 


.151 


24 


25 


.0179 


.02 


.067 


.0204 


.116 


.148 


25 


26 


.01594 


.018 


.060 


.0181 


.093 


.146 


26 


27 


.014195 


.016 


.053 


.0173 


.083 


.143 


21 


28 


.012641 


.014 


.047 


.0162 


.074 


.139 


28 


29 


.011257 


.013 


.044 


.0150 


.061 


.134 


29 


30 


.010025 


.012 


.040 


.0140 


.054 


.127 


30 


31 


.008928 


.01 


.0333 


.0132 


.050 


.120 


31 


32 


.00795 


.009 


.0300 


.0128 


.046 


.115 


32 


33 


.00708 


.008 


.0266 


.0118 


.037 


.112 


33 


34 


.006304 


.007 


.0233 


.0104 


.030 


.110 


34 


35 


.005614 


.005 


.0167 


.0095 


.025 


.108 


35 


36 


.005 


.004 


.0133 


.0090 


.025 


.108 


36 


37 


.004453 










.103 


37 


38 


.003965 










.101 


38 


39 


.003531 










.099 


39 


40 


.003144 










.092 


40 



SHRINKAGE TABLE 

For use in casting the metals mentioned. Figures are based on walls about .25" 
thick. Thicker walls will shrink somewhat more and thinner walls less. 

Pure aluminum 203" per foot 

Xo. 12 aluminum alloy 156" " 

Cast iron 125" " 

Iron, cast or malleable 125" " 

Steel 250" " 

Brass 1875" " 

Zinc 3215" " 

Lead 3125" " 

Copper 1875" " 

90 



SIZES OF NUMBERS OF THE UNITED STATES STANDARD GAUGE FOR 
SHEET AND PLATE IRON AND STEEL 

An Act Establishing a Standard Gauge for Sheet and Plate Iron and Steel 

Be it enacted by the Seriate and House of Representatives of the United States of 
America in Congress assembled : That for the purpose of securing uniformity the fol- 
lowing is established as the only gauge for sheet and plate iron and steel in the United 
States of America namely: 





Approximate 


Approximate 


Weight per 


Weight per 


Number of 


Thickness in 


Thickness in 


Square Foot 


Square Foot 


Gauge 


Fractions of 


Decimal Parts 


in Ounces 


in Pounds 




an Inch 


of an Inch 


Avoirdupois 


Avoirdupois 


0000000 


V2 


.5 


320 


20.00 


000000 


1%2 


.46875 


300 


18.75 


00000 


16 


.4375 


280 


17.50 


0000 


^%2 


.40625 


260 


16.25 


000 


^8 


.375 


240 


15.00 


00 


"/32 


.34375 


220 


13.75 





A 


.3125 


200 


12.50 


1 


%2 


.28125 


180 


11.25 


2 


1-/64 


.265625 


170 


10.625 


3 


Va 


.25 


160 


10.00 


4 


1%4 


.234375 


ISO 


9.375 


5 


732 


.21875 


140 


8.75 


6 


1%4 


.203125 


130 


8.125 


7 


3 


.1875 


120 


7.5 


8 


"/64 


.171875 


110 


6.875 


9 


%2 


.15625 


100 


6.25 


10 


%4 


.140625 


90 


5.625 


11 


V% 


.125 


80 


5.00 


12 


'/(i4 


.109375 


70 


4.375 


13 


%2 


.09375 


60 


3.75 


14 


%4 


.078125 


50 


3.125 


15 


•>i28 


.0703125 


45 


2.81253 


16 


~h 


.0625 


40 


2.5 


17 


^Am 


.05625 


36 


2.25 


18 


.720 


.05 


32 


2 


19 


7l60 


.04375 


28 


L75 


20 


3/^80 


.0375 


24 


1.50 


21 


"7320 


.034375 


22 


1.375 


22 


732 


.03125 


20 


1.25 


23 


%20 


.028125 


18 


1.25 


24 


_740 


.025 


16 


1. 


25 


%20 


.021875 


14 


.875 


26 


^160 


.01875 


12 


.75 


27 


"/ko 


.0171875 


11 


.6875 


28 


764 


.015625 


10 


.625 


29 


%40 


.0140625 


9 


.5625 


30 


_780 


.0125 


8 


.5 


31 


'/ijiO 


.0109375 


7 


.4375 


32 


1M280 


.01015625 


6/2 


.40625 


33 


%20 


.009375 


6 


.375 


34 


171 280 


.00859375 


5/2 


.34375 


35 


%40 


.0078125 


5 


.3125 


36 


^1280 


.00703125 


^Vz 


.28125 


37 


1%560 


.006640625 


4^ 


.265625 


38 


7l60 


.00625 


4 


.25 



And on and after July first, eighteen hundred and ninety-three, the same and no other shall be 
used in determining duties and taxes levied by the United States of America on sheet and plate iron 
and steel". But this act shall not be construed to increase duties upon any articles which may be 
imported. 

Sec. 3. That in the practical use and application of the standard gauge hereby established a 
variation of two and one-half per cent, either way may be allowed. 

Approved March 3, 1893. 



91 



LIST OF NINE DIFFERENT STANDARD GAUGES USED IN THE 
UNITED STATES 

DECIMAL EQUIV.\LENTS (Inches) 





^ V 


(L> 


a 




v_ 


c 










oii 


V 

be 

=! 
nl 


a 







V 

i 


Cm CD 


T3 C 

■■c ^ c 




T3 a; 


be 

3 


J! 


> 

li 

wt: 


o 

M-4 


O 




i^ 


^ 


-a I 


3 


^^ 1 


% 







25 



3 
1^ 


o 


C a 


If 

Km 


J3 


al NT 1 "* c 


— n> 


m— ' -^ 





-0 „ 





■■S a 


.§ >■ 


6 






Ml 


3 tn i 

3 i-'^ 


3 -^ u 






6 


fa 




8-0 














This g-auge .0083 


8-0 


^l 


.01563 


7-0 










." .'50c 





from one to .0087 | 


7-0 


^ 


.03125 


6-0 








.'464 


.469 


.... 


three thous- .009 




6-0 


iV 


.625 


5-0 








.432 


.438 




andths larger .010 


.... 


5-0 


A 


.07813 


4-0 


.460 


.'454 


.'394 


.400 


.406 




than same Nos. .011 




4-0 


i^ 


.09735 


3-0 


.410 


.425 


.363 


.372 


.375 




of Stubbs steel j .012 


' .632' 


3-0 


A 


.10938 


2-0 


.365 


.380 


.331 


.348 


3.44 




wire gauge .013 


.045 


2-0 


y& 


.125 





.325 
.289 


.340 
.300 


.307 
.283 


.334 
.300 


.313 
.281 




Oil 


i .058 
■. .071 



1 


A 


14063 


1 


'.Hi 


.228 .016 


!l5625 


2 


.258 


2.84 


.263 


.276 


.266 


.219 


.221 ' .017 


.084 


2 


hi 


.17188 


3 


.229 


.259 


.244 


.252 


.250 


.212 


.213 ' .018 


.097 


3 


l\ 


.1875 


4 


.204 


.238 


.225 


.232 


.234 


.207 


.209 .019 


.110 


4 


M 


.20313 


5 


.182 


.220 


.207 


.212 


.219 


.204 


.206 .020 


.124 


5 


^\ 


.21875 


6 


.162 


.203 


.192 


.192 


.203 


.201 


.204 .022 


.137 


6 


M 


.23438 


7 


.144 


.180 


.177 


.176 


.188 


.199 


.201 i .0 


23 


.150 


7 


% 


.25 


8 


.128 


.165 


.162 


.160 


.172 


.197 


.199 .024 


.163 


8 


ii 


.26563 


9 


.114 


.148 


.148 


.144 


.156 


.194 


.196 1 .026 


.176 


9 




.28125 


10 


.102 


.134 


.135 


.128 


.141 


.191 


.194 .027 


.189 


10 


Jl 


.29688 


11 


.091 


.120 


.121 


.116 


.125 


.188 


.141 1 .0 


72 


.426 


28 


iJ 


.57813 


12 


.081 


.109 


.106 


.104 


.109 


.185 


.189 I .030 


.216 


12 


U 


.32813 


13 


.072 


.095 


.092 


.092 


.094 


.182 


.191 ' .028 


.203 


11 


A 


.3125 


14 


.064 


.083 


.080 


.080 


.078 


.180 


.185 ' .031 


.229 


13 


a 


.34375 


15 


.057 


.072 


.072 


.072 


.070 


.178 


.182 .0 


33 


.242 


14 


ii 


.35938 


16 


.051 


.065 


.063 


.064 


.063 


.175 


.180 , .035 


.255 


15 


Vs 


.375 


17 


.045 


.058 


.054 


.056 


.056 


.172 


.177 .036 


.268 


16 


II 


.39063 


18 


.040 


.049 


.048 


.048 


.050 


.168 


.173 .038 


.282 


17 


M 


.40625 


19 


.036 


.042 


.041 


.040 


.044 


.164 


.170 .040 


1 .295 


18 


U 


.42188 


20 


.032 


.035 


.035 


.036 


.038 


.161 


.166 ' .041 


1 .308 


19 


tV 


.4375 


21 


.028 


.032 


.032 


.032 


.034 


.157 


.161 i .043 


.321 


20 


§1 


.45313 


22 


.025 


.028 


.029 


.028 


.031 


.155 


.15^ .046 


.334 


21 


ss 


.46875 


23 


.023 


.025 


.026 


.024 


.028 


.153 


.157 .048 


.347 


22 


ii 


.48438 


24 


.020 


.022 


.023 


.022 


.025 


.151 


.154 .051 


.360 


23 


^ 


.5 


25 


.018 


.020 


.020 


.020 


.022 


.148 


.152 I .055 


.374 


24 


tl 


.51563 


26 


.016 


.018 


.018 


.018 


.019 


.146 


.150 .0 


59 


.387 


25 


il 


.53125 


27 


.0141 


.016 


.0173 


.016 


4 .017 


1 .143 


.147 .0 


63 


.400 


26 


S| 


.54688 


28 


.0126 


.014 


.0162 


.014 


9 .015 


6 .139 


.144 .0 


66 


.413 


27 




.5625 


29 


.0112 


.013 


.015 


.013 


6 .014 


.134 


.136 .0 


76 


.439 


29 


11 


.59375 


30 


.010 


.012 


0.14 


.012 


4 .012 


5 .127 


.129 .0 


80 


.453 


30 


11 


.60938 


31 


.0089 


.010 


.0132 


.011 


6 .010 


9 .120 


.120 




.466 


31 




.625 


32 


.0079 


.009 


.0128 


.010 


8 .010 


1 .115 


.116 




.479 


32 


fl 


.64063 


33 


.007 


.008 


.0118 


.010 


.009 


3 .112 


.113 




.492 


33 


ih 


.65625 


34 


.0063 


.007 


.0104 


.009 


2 .008 


5 .110 


.111 




.505 


34 


II 


.67188 


35 


.0056 


.005 


.0095 


.008 


4 .007 


8 .108 


.110 




.518 


35 


u 


.6875 


r.fi 


.005 


.004 


.009 


.007 


6 .007 


.106 


.1065 i . 




.532 


36 


II 


.70313 


37 


.0044 






.006 


8 .006 


6 .103 


.104 1 . 




.545 


37 




.71875 


38 


.0039 






.006 


.006 


2 .101 


.1015 




.558 


38 


II 


.73438 


39 


.0035 






.005 


2 ... 


.099 


.0995 




.571 


39 


H 


.75 


40 


.0031 






.004 


8 ... 


.097 


.098 




.584 


40 


n 


.76563 


41 












.095 


.096 




.597 


41 


M 


.78125 


42 












.092 


.094 




.611 


42 


H 


.79688 


43 












.088 


.089 




.624 


43 


II 


.8125 


44 












.085 


.086 




.637 


44 


n 


.82813 


45 












.081 


.082 




.650 


45 


n 


.84375 


46 












.079 


.081 




.663 


46 


II 


.85938 


47 












.077 


.079 




.676 


47 


% 


.875 


48 












.075 


.076 




.690 


48 


Si 


.89063 


49 












.072 


.073 




.703 


49 


?-s 


.90625 


50 












.069 


.070 




.716 


50 


SI 


.92188 



A 234 

B 238 

C 242 

D 246 

K 250 

P 257 

G 261 

H 266 



Letter Sizes Stubbs Steel Wire 

1 272 

J 277 

K 281 

L 290 

M 295 

N 302 

O 316 

P 323 

Q 332 



R 339 

S 348 

T 358 

U 368 

V 377 

W 3S6 

X 397 

Y 404 

Z 413 

92 



Index 



Page 
A 

Accuracy 11,51,52 

Advantages 11 

Alloys, die cast 21 

Table of 83 

Allowances for reaming 52 

For shrinkage 52 

Aluminum alloys 22 

Properties of 24 

Chemical properties of 24 

Chemical finishes 78 

Soldering 79 

Pickling 75 

Polishing 7i 

Plating 75 

Welding 81 

Anti-friction metals -50, 32 

Assembling, reduction of 12 

B 

Bab])itts 30,32 

Formulas 85 

Baked enamels 85 

Beads 44 

Black finish 78 

Brass die casting 8, 2! 

Brass plating 7^ 

Bushing inserts 56 

C 

Cements 81 

Changes on dies 39 

Cleaning, plating method 69 

Solutions 70 

Clearance for tools 50 

Clothias process 58 

Cold enamels 77 

Coloring aluminum 78 

Combination dies 40 

Compression casting chamber 19,58 

Copper plating 72 

Cores, crossing 40 

Interchangeable 40 

Cost 13, IS 

Cutting lubricants 67 

Steels 67 

Speeds 67 

D 

Deliveries, speed of 12 

Design, range of 11 

Devices using die-castings 9 

Die-casting definition 8 

Design 42 

Processes 58 

Die-casting, causes of inaccuracy 35 

Die assembly 37 

Design 34, 35, 36, 37, 38, 40 

Life of 34 

Materials 38 

Mounting 63 

Operation 63 



Page 

Position 60 

Removal 41 

Surfaces 37 

Draft 52 

Dull tools 67 

E 

Ejector pin marks 42 

Elbows 46 

Electro plating 69 

Engraving 49 

Estimates, suggestions on 15. 16, 17, 18 

F 

Fillets 44 

Finish 11 

Finishes, methods of applying 74 

Fluxes for soldering 79 

G 

Gating 38, 64 

Gauges 53 

Gears 49 

Gold plating 74 

Grinding 68 

Galvanic action 24, 27 

H 

High pot 61 

I 

Impurities in metals 21, 22, 28 

Inserts 54 

Introduction 7 

L 

Lacquers, enamels, etc 77 

Lead alloys 30 

M 

Machining advantages 13 

Machining methods 67 

Manufacturing advantages 13 

Metals used 19 

Metal finishes 77 

N 
Nickel plating 71 

P 

Plating instructions 69 to 76 

Pipe threads 48 

Plunger types 59 

Precision Castings Co 7 

Pressures 19,36 

Processes of die-casting 58 

Properties of zinc 27 

Punchings, inserts 57 

Q 

(Juantities 15 

S 

Shrinkage, no allowance for 38, 51 

Silver plating 74 

Sizes in fractions 53 



Page 

Soldering die-castings 79 

Solders, table of 87 

Springs, inserts 57 

Sprue cutters 64 

Studs, inserts 56 

Suggestions to purchasers IS 

T 
Tables — 

British thermal unit 84 

Co-efficients of friction 88 

Drill sizes for threads 89 

Electro-chemical series 86 

Gauges for various materials 84 

How to find degrees Fahrenheit or Centi- 
grade 84 

Metric conversion tables 86 

Nine gauges in general use 92 

Non-ferrous metal tubing tolerances 87 

Physical properties of metals 85 

Precision alloys 83 

Shrinkage table 90 

Solders 87 

Standard gauges for iron and stee! 91 

Stubbs steel wire sizes 92 

Useful information 84 



Page 

Weights and measures 88 

Wire gauges 90 

Tap holes, sizes 67 

Taper 52 

Threads 48 

Tilting pot 60 

Tin plating 73 

Tin alloys 29 

Tools, design of 67 

Tubing inserts 57 

U 
Undercuts 44 

V 

\ acuum processes 62 

N'ariation, limits of 52 

\'ariation in holes, etc 52 

W 

Walls, thickness 42 

Webs 46 

Weights of die-castings 42 

Z 

Zinc alloys 25 

Properties of 27 

Impurities 28 



Index of Illustrations 



Page 

Precision Factory, Fayetteville 4 

Precision Factory, Pontiac 7 

Water pump parts 8 

Speedometer frame 9 

Dispensing machine parts 10 

Sealing machine parts 14 

Steering column parts 16 

Liberty Motor part 17 

Cord tire mold insert 18 

Parts for motors, instruments, etc 19 

Phonograph parts 20 

Electric motor and instrument parts 23 

Aeroplane speedometer 25 

Speedometer parts 26 

Bouchonj 28 

Babbitt bushings 29 

Babbitt bearings 31 

Bearing retainers and shims 33 

Die Shop, Fayetteville 34 

Pulley wheel die 35 

Number wheel die 36 

Steering column sector die 37 

Die block on miller 38 

Die and part for plate 39 

Die worker "checking up" 40 

Handles, knobs 41 



Page 

Milking machine part 42 

Magneto and generator parts 43 

Soda fountain parts 45 

Elbows 46 

Moving picture machine plates 47 

Threaded parts 48 

Pipe threads 48 

Gears 49 

Check protector wheel 49 

Drill stands 50 

Number wheel 50 

Number wheels 51 

Pulleys 53 

Magneto housing 54 

Parts showing various inserts 55 

Bushing inserts 56 

Stud inserts 56 

Punched insert 57 

Vending machine parts 59 

Four parts 61 

Trimming room 65 

Presses 66 

Carburetor parts 67 

Strut sockets 68 

Vane for aerial bomb 76 

Fire Extinguisher parts 81 



w 



^^^^ 



Wdr]:JHHM?li1 



120 90 









































O.. *.T»' .^0 


































• " • AT 











jp-n*.. •; 



•' 4- % '- 



,i^ o » " » 













^\/\ 























jPv\ 














^^^^^' 



^'^.P^'^^ 



_ aO^ 






i^ ^. 













HECKMAN m 
BINDERY INC. |§| 

^ FEB 90 

N. MANCHESTER, 
INDIANA 46962 




■> p. " » .» ■^j. 







^. "^^^^ .*f' 









>. ^r^rs A^ 



